656881221 has 8 divisors (see below), whose sum is σ = 876072960. Its totient is φ = 437805152.

The previous prime is 656881217. The next prime is 656881231. The reversal of 656881221 is 122188656.

656881221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 656881221 - 2² = 656881217 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 656881221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (656881231) 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, 14661 + ... + 39098.

It is an arithmetic number, because the mean of its divisors is an integer number (109509120).

Almost surely, 2^656881221 is an apocalyptic number.

It is an amenable number.

656881221 is a deficient number, since it is larger than the sum of its proper divisors (219191739).

656881221 is a wasteful number, since it uses less digits than its factorization.

656881221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57835.

The product of its digits is 46080, while the sum is 39.

The square root of 656881221 is about 25629.6941261498. The cubic root of 656881221 is about 869.2851930190.

The spelling of 656881221 in words is "six hundred fifty-six million, eight hundred eighty-one thousand, two hundred twenty-one".