56221561521 has 12 divisors (see below), whose sum is σ = 82321374148. Its totient is φ = 36967601664.

The previous prime is 56221561463. The next prime is 56221561567. The reversal of 56221561521 is 12516512265.

56221561521 is a `hidden beast` number, since 5 + 6 + 2 + 2 + 15 + 615 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 33064330896 + 23157230625 = 181836^2 + 152175^2 .

It is not a de Polignac number, because 56221561521 - 2¹³ = 56221553329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (56221561021) 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 11 ways as a sum of consecutive naturals, for example, 42785920 + ... + 42787233.

Almost surely, 2^56221561521 is an apocalyptic number.

It is an amenable number.

56221561521 is a deficient number, since it is larger than the sum of its proper divisors (26099812627).

56221561521 is a wasteful number, since it uses less digits than its factorization.

56221561521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85573232 (or 85573229 counting only the distinct ones).

The product of its digits is 36000, while the sum is 36.

The spelling of 56221561521 in words is "fifty-six billion, two hundred twenty-one million, five hundred sixty-one thousand, five hundred twenty-one".