191900000 has 144 divisors (see below), whose sum is σ = 501999120. Its totient is φ = 72000000.

The previous prime is 191899997. The next prime is 191900003. The reversal of 191900000 is 9191.

It is an interprime number because it is at equal distance from previous prime (191899997) and next prime (191900003).

It is a super-2 number, since 2×191900000² = 73651220000000000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191900003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1899950 + ... + 1900050.

It is an arithmetic number, because the mean of its divisors is an integer number (3486105).

Almost surely, 2^191900000 is an apocalyptic number.

191900000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 191900000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (250999560).

191900000 is an abundant number, since it is smaller than the sum of its proper divisors (310099120).

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

191900000 is an equidigital number, since it uses as much as digits as its factorization.

191900000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155 (or 127 counting only the distinct ones).

The product of its (nonzero) digits is 81, while the sum is 20.

The square root of 191900000 is about 13852.7975513973. The cubic root of 191900000 is about 576.7996545095.

Adding to 191900000 its reverse (9191), we get a palindrome (191909191).

The spelling of 191900000 in words is "one hundred ninety-one million, nine hundred thousand".