656906881 has 8 divisors (see below), whose sum is σ = 661324520. Its totient is φ = 652503168.

The previous prime is 656906867. The next prime is 656906891. The reversal of 656906881 is 188609656.

It can be written as a sum of positive squares in 4 ways, for example, as 558896881 + 98010000 = 23641^2 + 9900^2 .

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 656906881 - 2⁵ = 656906849 is a prime.

It is a super-2 number, since 2×656906881² = 863053300610296322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (656906801) 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, 101515 + ... + 107791.

It is an arithmetic number, because the mean of its divisors is an integer number (82665565).

Almost surely, 2^656906881 is an apocalyptic number.

It is an amenable number.

656906881 is a deficient number, since it is larger than the sum of its proper divisors (4417639).

656906881 is a wasteful number, since it uses less digits than its factorization.

656906881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6963.

The product of its (nonzero) digits is 622080, while the sum is 49.

The square root of 656906881 is about 25630.1947124871. The cubic root of 656906881 is about 869.2965119439.

The spelling of 656906881 in words is "six hundred fifty-six million, nine hundred six thousand, eight hundred eighty-one".