77640732 has 72 divisors (see below), whose sum is σ = 220575264. Its totient is φ = 22847616.

The previous prime is 77640691. The next prime is 77640733. The reversal of 77640732 is 23704677.

77640732 is a `hidden beast` number, since 7 + 7 + 640 + 7 + 3 + 2 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77640733) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7158 + ... + 14370.

Almost surely, 2^77640732 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 77640732, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110287632).

77640732 is an abundant number, since it is smaller than the sum of its proper divisors (142934532).

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

77640732 is a wasteful number, since it uses less digits than its factorization.

77640732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7259 (or 7254 counting only the distinct ones).

The product of its (nonzero) digits is 49392, while the sum is 36.

The square root of 77640732 is about 8811.3978459720. The cubic root of 77640732 is about 426.6088628832.

The spelling of 77640732 in words is "seventy-seven million, six hundred forty thousand, seven hundred thirty-two".