656061936521 has 4 divisors (see below), whose sum is σ = 657941770500. Its totient is φ = 654182102544.

The previous prime is 656061936511. The next prime is 656061936539. The reversal of 656061936521 is 125639160656.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 228614034496 + 427447902025 = 478136^2 + 653795^2 .

It is a cyclic number.

It is not a de Polignac number, because 656061936521 - 2¹⁰ = 656061935497 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 656061936521.

It is not an unprimeable number, because it can be changed into a prime (656061936511) 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 3 ways as a sum of consecutive naturals, for example, 939916466 + ... + 939917163.

It is an arithmetic number, because the mean of its divisors is an integer number (164485442625).

Almost surely, 2^656061936521 is an apocalyptic number.

It is an amenable number.

656061936521 is a deficient number, since it is larger than the sum of its proper divisors (1879833979).

656061936521 is a wasteful number, since it uses less digits than its factorization.

656061936521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1879833978.

The product of its (nonzero) digits is 1749600, while the sum is 50.

The spelling of 656061936521 in words is "six hundred fifty-six billion, sixty-one million, nine hundred thirty-six thousand, five hundred twenty-one".