656640339 has 4 divisors (see below), whose sum is σ = 875520456. Its totient is φ = 437760224.

The previous prime is 656640331. The next prime is 656640343. The reversal of 656640339 is 933046656.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 656640339 - 2³ = 656640331 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 656640339.

It is not an unprimeable number, because it can be changed into a prime (656640331) 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, 109440054 + ... + 109440059.

It is an arithmetic number, because the mean of its divisors is an integer number (218880114).

Almost surely, 2^656640339 is an apocalyptic number.

656640339 is a deficient number, since it is larger than the sum of its proper divisors (218880117).

656640339 is a wasteful number, since it uses less digits than its factorization.

656640339 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218880116.

The product of its (nonzero) digits is 349920, while the sum is 42.

The square root of 656640339 is about 25624.9944195116. The cubic root of 656640339 is about 869.1789227884.

The spelling of 656640339 in words is "six hundred fifty-six million, six hundred forty thousand, three hundred thirty-nine".