77931520 has 88 divisors (see below), whose sum is σ = 193367808. Its totient is φ = 30105600.

The previous prime is 77931493. The next prime is 77931533. The reversal of 77931520 is 2513977.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 158475 + ... + 158965.

Almost surely, 2^77931520 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 77931520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96683904).

77931520 is an abundant number, since it is smaller than the sum of its proper divisors (115436288).

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

77931520 is a wasteful number, since it uses less digits than its factorization.

77931520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 547 (or 529 counting only the distinct ones).

The product of its (nonzero) digits is 13230, while the sum is 34.

The square root of 77931520 is about 8827.8830984557. The cubic root of 77931520 is about 427.1407923855.

The spelling of 77931520 in words is "seventy-seven million, nine hundred thirty-one thousand, five hundred twenty".