77685840 has 60 divisors (see below), whose sum is σ = 260897364. Its totient is φ = 20716032.

The previous prime is 77685833. The next prime is 77685847. The reversal of 77685840 is 4858677.

77685840 is a `hidden beast` number, since 7 + 7 + 68 + 584 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (77685833) and next prime (77685847).

It can be written as a sum of positive squares in 2 ways, for example, as 30735936 + 46949904 = 5544^2 + 6852^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77685847) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 53229 + ... + 54668.

Almost surely, 2^77685840 is an apocalyptic number.

It is an amenable number.

77685840 is an abundant number, since it is smaller than the sum of its proper divisors (183211524).

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

77685840 is a wasteful number, since it uses less digits than its factorization.

77685840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107916 (or 107907 counting only the distinct ones).

The product of its (nonzero) digits is 376320, while the sum is 45.

The square root of 77685840 is about 8813.9571135784. The cubic root of 77685840 is about 426.6914644875.

The spelling of 77685840 in words is "seventy-seven million, six hundred eighty-five thousand, eight hundred forty".