77640688 has 40 divisors (see below), whose sum is σ = 159672320. Its totient is φ = 36469440.

The previous prime is 77640677. The next prime is 77640691. The reversal of 77640688 is 88604677.

It is a super-2 number, since 2×77640688² = 12056152866226688, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37603 + ... + 39613.

It is an arithmetic number, because the mean of its divisors is an integer number (3991808).

Almost surely, 2^77640688 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 77640688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (79836160).

77640688 is an abundant number, since it is smaller than the sum of its proper divisors (82031632).

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

77640688 is a wasteful number, since it uses less digits than its factorization.

77640688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2165 (or 2159 counting only the distinct ones).

The product of its (nonzero) digits is 451584, while the sum is 46.

The square root of 77640688 is about 8811.3953492055. The cubic root of 77640688 is about 426.6087822950.

The spelling of 77640688 in words is "seventy-seven million, six hundred forty thousand, six hundred eighty-eight".