77157640 has 64 divisors (see below), whose sum is σ = 207048960. Its totient is φ = 25301760.

The previous prime is 77157631. The next prime is 77157653. The reversal of 77157640 is 4675177.

77157640 = 2261² + 2262² + ... + 2275².

It is a self number, because there is not a number n which added to its sum of digits gives 77157640.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 450 + ... + 12430.

It is an arithmetic number, because the mean of its divisors is an integer number (3235140).

Almost surely, 2^77157640 is an apocalyptic number.

77157640 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 77157640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103524480).

77157640 is an abundant number, since it is smaller than the sum of its proper divisors (129891320).

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

77157640 is a wasteful number, since it uses less digits than its factorization.

77157640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12022 (or 12018 counting only the distinct ones).

The product of its (nonzero) digits is 41160, while the sum is 37.

The square root of 77157640 is about 8783.9421673870. The cubic root of 77157640 is about 425.7222137809.

The spelling of 77157640 in words is "seventy-seven million, one hundred fifty-seven thousand, six hundred forty".