78502644 has 72 divisors (see below), whose sum is σ = 218207808. Its totient is φ = 23598720.

The previous prime is 78502621. The next prime is 78502679. The reversal of 78502644 is 44620587.

78502644 is a `hidden beast` number, since 7 + 8 + 5 + 0 + 2 + 644 = 666.

It is a super-2 number, since 2×78502644² = 12325330229981472, which contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 78502599 and 78502608.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 53529 + ... + 54975.

It is an arithmetic number, because the mean of its divisors is an integer number (3030664).

Almost surely, 2^78502644 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 78502644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109103904).

78502644 is an abundant number, since it is smaller than the sum of its proper divisors (139705164).

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

78502644 is a wasteful number, since it uses less digits than its factorization.

78502644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1605 (or 1600 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 36.

The square root of 78502644 is about 8860.1717816304. The cubic root of 78502644 is about 428.1816927357.

The spelling of 78502644 in words is "seventy-eight million, five hundred two thousand, six hundred forty-four".