77685440 has 112 divisors (see below), whose sum is σ = 214579200. Its totient is φ = 26237952.

The previous prime is 77685409. The next prime is 77685449. The reversal of 77685440 is 4458677.

It is a tau number, because it is divible by the number of its divisors (112).

It is not an unprimeable number, because it can be changed into a prime (77685449) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 176741 + ... + 177179.

Almost surely, 2^77685440 is an apocalyptic number.

77685440 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77685440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107289600).

77685440 is an abundant number, since it is smaller than the sum of its proper divisors (136893760).

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

77685440 is a wasteful number, since it uses less digits than its factorization.

77685440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 542 (or 532 counting only the distinct ones).

The product of its (nonzero) digits is 188160, while the sum is 41.

The square root of 77685440 is about 8813.9344222657. The cubic root of 77685440 is about 426.6907321495.

It can be divided in two parts, 77685 and 440, that added together give a 7-th power (78125 = 5⁷).

The spelling of 77685440 in words is "seventy-seven million, six hundred eighty-five thousand, four hundred forty".