77158991520 has 576 divisors, whose sum is σ = 295423783200. Its totient is φ = 18338052096.

The previous prime is 77158991477. The next prime is 77158991521. The reversal of 77158991520 is 2519985177.

77158991520 is a `hidden beast` number, since 7 + 7 + 1 + 589 + 9 + 1 + 52 + 0 = 666.

It can be written as a sum of positive squares in 16 ways, for example, as 55539406224 + 21619585296 = 235668^2 + 147036^2 .

It is not an unprimeable number, because it can be changed into a prime (77158991521) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2660654866 + ... + 2660654894.

Almost surely, 2^77158991520 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77158991520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (147711891600).

77158991520 is an abundant number, since it is smaller than the sum of its proper divisors (218264791680).

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

77158991520 is an equidigital number, since it uses as much as digits as its factorization.

77158991520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147 (or 52 counting only the distinct ones).

The product of its (nonzero) digits is 1587600, while the sum is 54.

The spelling of 77158991520 in words is "seventy-seven billion, one hundred fifty-eight million, nine hundred ninety-one thousand, five hundred twenty".