647661725 has 24 divisors (see below), whose sum is σ = 814609320. Its totient is φ = 510750720.

The previous prime is 647661719. The next prime is 647661803. The reversal of 647661725 is 527166746.

It can be written as a sum of positive squares in 12 ways, for example, as 126270169 + 521391556 = 11237^2 + 22834^2 .

It is not a de Polignac number, because 647661725 - 2⁶ = 647661661 is a prime.

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, 991499 + ... + 992151.

It is an arithmetic number, because the mean of its divisors is an integer number (33942055).

Almost surely, 2^647661725 is an apocalyptic number.

It is an amenable number.

647661725 is a deficient number, since it is larger than the sum of its proper divisors (166947595).

647661725 is a wasteful number, since it uses less digits than its factorization.

647661725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1169 (or 1164 counting only the distinct ones).

The product of its digits is 423360, while the sum is 44.

The square root of 647661725 is about 25449.1989068418. The cubic root of 647661725 is about 865.1991366618.

The spelling of 647661725 in words is "six hundred forty-seven million, six hundred sixty-one thousand, seven hundred twenty-five".