656475861921 has 16 divisors (see below), whose sum is σ = 954888096000. Its totient is φ = 397858277520.

The previous prime is 656475861893. The next prime is 656475861929. The reversal of 656475861921 is 129168574656.

It is not a de Polignac number, because 656475861921 - 2¹⁴ = 656475845537 is a prime.

It is not an unprimeable number, because it can be changed into a prime (656475861929) 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 in 15 ways as a sum of consecutive naturals, for example, 3387186 + ... + 3575748.

It is an arithmetic number, because the mean of its divisors is an integer number (59680506000).

Almost surely, 2^656475861921 is an apocalyptic number.

It is an amenable number.

656475861921 is a deficient number, since it is larger than the sum of its proper divisors (298412234079).

656475861921 is a wasteful number, since it uses less digits than its factorization.

656475861921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 294076.

The product of its digits is 21772800, while the sum is 60.

The spelling of 656475861921 in words is "six hundred fifty-six billion, four hundred seventy-five million, eight hundred sixty-one thousand, nine hundred twenty-one".