77831280 has 100 divisors (see below), whose sum is σ = 270342072. Its totient is φ = 20753280.

The previous prime is 77831279. The next prime is 77831309. The reversal of 77831280 is 8213877.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 475 + ... + 12485.

Almost surely, 2^77831280 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 77831280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135171036).

77831280 is an abundant number, since it is smaller than the sum of its proper divisors (192510792).

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

77831280 is a wasteful number, since it uses less digits than its factorization.

77831280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12036 (or 12021 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 77831280 is about 8822.2038063060. The cubic root of 77831280 is about 426.9575761299.

The spelling of 77831280 in words is "seventy-seven million, eight hundred thirty-one thousand, two hundred eighty".