656871493 has 4 divisors (see below), whose sum is σ = 678060928. Its totient is φ = 635682060.

The previous prime is 656871473. The next prime is 656871521. The reversal of 656871493 is 394178656.

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 656871493 - 2⁵ = 656871461 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (656871433) 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, 10594671 + ... + 10594732.

It is an arithmetic number, because the mean of its divisors is an integer number (169515232).

Almost surely, 2^656871493 is an apocalyptic number.

It is an amenable number.

656871493 is a deficient number, since it is larger than the sum of its proper divisors (21189435).

656871493 is a wasteful number, since it uses less digits than its factorization.

656871493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21189434.

The product of its digits is 1088640, while the sum is 49.

The square root of 656871493 is about 25629.5043455780. The cubic root of 656871493 is about 869.2809018078.

The spelling of 656871493 in words is "six hundred fifty-six million, eight hundred seventy-one thousand, four hundred ninety-three".