647125657 has 4 divisors (see below), whose sum is σ = 660894336. Its totient is φ = 633356980.

The previous prime is 647125649. The next prime is 647125663. The reversal of 647125657 is 756521746.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 647125657 - 2³ = 647125649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (647125627) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6884269 + ... + 6884362.

It is an arithmetic number, because the mean of its divisors is an integer number (165223584).

Almost surely, 2^647125657 is an apocalyptic number.

It is an amenable number.

647125657 is a deficient number, since it is larger than the sum of its proper divisors (13768679).

647125657 is a wasteful number, since it uses less digits than its factorization.

647125657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13768678.

The product of its digits is 352800, while the sum is 43.

The square root of 647125657 is about 25438.6646072470. The cubic root of 647125657 is about 864.9603630473.

The spelling of 647125657 in words is "six hundred forty-seven million, one hundred twenty-five thousand, six hundred fifty-seven".