656431647 has 8 divisors (see below), whose sum is σ = 878472960. Its totient is φ = 436005720.

The previous prime is 656431637. The next prime is 656431651. The reversal of 656431647 is 746134656.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 656431647 - 2⁶ = 656431583 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 656431599 and 656431608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (656431637) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 402897 + ... + 404522.

It is an arithmetic number, because the mean of its divisors is an integer number (109809120).

Almost surely, 2^656431647 is an apocalyptic number.

656431647 is a deficient number, since it is larger than the sum of its proper divisors (222041313).

656431647 is a wasteful number, since it uses less digits than its factorization.

656431647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 807693.

The product of its digits is 362880, while the sum is 42.

The square root of 656431647 is about 25620.9220560073. The cubic root of 656431647 is about 869.0868328488.

The spelling of 656431647 in words is "six hundred fifty-six million, four hundred thirty-one thousand, six hundred forty-seven".