77639840 has 48 divisors (see below), whose sum is σ = 184796640. Its totient is φ = 30823680.

The previous prime is 77639839. The next prime is 77639869. The reversal of 77639840 is 4893677.

It is a junction number, because it is equal to n+sod(n) for n = 77639791 and 77639800.

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, 20495 + ... + 23985.

It is an arithmetic number, because the mean of its divisors is an integer number (3849930).

Almost surely, 2^77639840 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 77639840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92398320).

77639840 is an abundant number, since it is smaller than the sum of its proper divisors (107156800).

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

77639840 is a wasteful number, since it uses less digits than its factorization.

77639840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3645 (or 3637 counting only the distinct ones).

The product of its (nonzero) digits is 254016, while the sum is 44.

The square root of 77639840 is about 8811.3472295671. The cubic root of 77639840 is about 426.6072291335.

The spelling of 77639840 in words is "seventy-seven million, six hundred thirty-nine thousand, eight hundred forty".