195139890 has 96 divisors (see below), whose sum is σ = 555984000. Its totient is φ = 47093760.

The previous prime is 195139883. The next prime is 195139897. The reversal of 195139890 is 98931591.

195139890 is a nontrivial binomial coefficient, being equal to C(19756, 2).

It is an interprime number because it is at equal distance from previous prime (195139883) and next prime (195139897).

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (195139897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 434386 + ... + 434834.

It is an arithmetic number, because the mean of its divisors is an integer number (5791500).

Almost surely, 2^195139890 is an apocalyptic number.

195139890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

195139890 is the 19755-th triangular number and also the 9878-th hexagonal number.

It is a practical number, because each smaller number is the sum of distinct divisors of 195139890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (277992000).

195139890 is an abundant number, since it is smaller than the sum of its proper divisors (360844110).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

195139890 is a wasteful number, since it uses less digits than its factorization.

195139890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 912 (or 909 counting only the distinct ones).

The product of its (nonzero) digits is 87480, while the sum is 45.

The square root of 195139890 is about 13969.2480112567. The cubic root of 195139890 is about 580.0276344344.

It can be divided in two parts, 19513 and 9890, that added together give a triangular number (29403 = T₂₄₂).

The spelling of 195139890 in words is "one hundred ninety-five million, one hundred thirty-nine thousand, eight hundred ninety".