656121656 has 8 divisors (see below), whose sum is σ = 1230228120. Its totient is φ = 328060824.

The previous prime is 656121637. The next prime is 656121659.

656121656 is nontrivially palindromic in base 10.

It is a tau number, because it is divible by the number of its divisors (8).

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (656121659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41007596 + ... + 41007611.

It is an arithmetic number, because the mean of its divisors is an integer number (153778515).

Almost surely, 2^656121656 is an apocalyptic number.

It is an amenable number.

656121656 is a deficient number, since it is larger than the sum of its proper divisors (574106464).

656121656 is a wasteful number, since it uses less digits than its factorization.

656121656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82015213 (or 82015209 counting only the distinct ones).

The product of its digits is 64800, while the sum is 38.

The square root of 656121656 is about 25614.8717740300. The cubic root of 656121656 is about 868.9500064597.

The spelling of 656121656 in words is "six hundred fifty-six million, one hundred twenty-one thousand, six hundred fifty-six".