78177990 has 64 divisors (see below), whose sum is σ = 205742592. Its totient is φ = 18854400.

The previous prime is 78177977. The next prime is 78177991. The reversal of 78177990 is 9977187.

It is a super-2 number, since 2×78177990² = 12223596240880200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78177991) 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 31 ways as a sum of consecutive naturals, for example, 79039 + ... + 80021.

It is an arithmetic number, because the mean of its divisors is an integer number (3214728).

Almost surely, 2^78177990 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78177990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102871296).

78177990 is an abundant number, since it is smaller than the sum of its proper divisors (127564602).

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

78177990 is a wasteful number, since it uses less digits than its factorization.

78177990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1245.

The product of its (nonzero) digits is 222264, while the sum is 48.

The square root of 78177990 is about 8841.8318237795. The cubic root of 78177990 is about 427.5906172256.

The spelling of 78177990 in words is "seventy-eight million, one hundred seventy-seven thousand, nine hundred ninety".