77655640 has 32 divisors (see below), whose sum is σ = 178990560. Its totient is φ = 30304000.

The previous prime is 77655629. The next prime is 77655661. The reversal of 77655640 is 4655677.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 77655593 and 77655602.

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, 22036 + ... + 25315.

It is an arithmetic number, because the mean of its divisors is an integer number (5593455).

Almost surely, 2^77655640 is an apocalyptic number.

It is an amenable number.

77655640 is an abundant number, since it is smaller than the sum of its proper divisors (101334920).

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

77655640 is a wasteful number, since it uses less digits than its factorization.

77655640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47403 (or 47399 counting only the distinct ones).

The product of its (nonzero) digits is 176400, while the sum is 40.

The square root of 77655640 is about 8812.2437551398. The cubic root of 77655640 is about 426.6361658969.

The spelling of 77655640 in words is "seventy-seven million, six hundred fifty-five thousand, six hundred forty".