646786624 has 105 divisors (see below), whose sum is σ = 1498924231. Its totient is φ = 276700160.

The previous prime is 646786579. The next prime is 646786633. The reversal of 646786624 is 426687646.

It is a happy number.

The square root of 646786624 is 25432.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 2 ways, for example, as 200732224 + 446054400 = 14168^2 + 21120^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 38046264 + ... + 38046280.

Almost surely, 2^646786624 is an apocalyptic number.

646786624 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

646786624 is the 25432-nd square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646786624

646786624 is an abundant number, since it is smaller than the sum of its proper divisors (852137607).

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

646786624 is an frugal number, since it uses more digits than its factorization.

646786624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102 (or 30 counting only the distinct ones).

The product of its digits is 2322432, while the sum is 49.

The cubic root of 646786624 is about 864.8092840256.

Multiplying 646786624 by its sum of digits (49), we get a square (31692544576 = 178024²).

The spelling of 646786624 in words is "six hundred forty-six million, seven hundred eighty-six thousand, six hundred twenty-four".