77688864 has 144 divisors (see below), whose sum is σ = 244127520. Its totient is φ = 23239680.

The previous prime is 77688859. The next prime is 77688889. The reversal of 77688864 is 46888677.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×77688864² = 12071119179220992, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 77688864.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 433927 + ... + 434105.

It is an arithmetic number, because the mean of its divisors is an integer number (1695330).

Almost surely, 2^77688864 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 77688864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122063760).

77688864 is an abundant number, since it is smaller than the sum of its proper divisors (166438656).

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

77688864 is a wasteful number, since it uses less digits than its factorization.

77688864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343 (or 332 counting only the distinct ones).

The product of its digits is 3612672, while the sum is 54.

The square root of 77688864 is about 8814.1286580127. The cubic root of 77688864 is about 426.6970008815.

The spelling of 77688864 in words is "seventy-seven million, six hundred eighty-eight thousand, eight hundred sixty-four".