20256670521 has 6 divisors (see below), whose sum is σ = 29259635210. Its totient is φ = 13504447008.

The previous prime is 20256670519. The next prime is 20256670531. The reversal of 20256670521 is 12507665202.

20256670521 is a `hidden beast` number, since 2 + 0 + 2 + 5 + 66 + 70 + 521 = 666.

It can be written as a sum of positive squares in only one way, i.e., 13348567296 + 6908103225 = 115536^2 + 83115^2 .

It is not a de Polignac number, because 20256670521 - 2¹ = 20256670519 is a prime.

It is a super-2 number, since 2×20256670521² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20256670531) 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 5 ways as a sum of consecutive naturals, for example, 1125370576 + ... + 1125370593.

Almost surely, 2^20256670521 is an apocalyptic number.

It is an amenable number.

20256670521 is a deficient number, since it is larger than the sum of its proper divisors (9002964689).

20256670521 is a wasteful number, since it uses less digits than its factorization.

20256670521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2250741175 (or 2250741172 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The spelling of 20256670521 in words is "twenty billion, two hundred fifty-six million, six hundred seventy thousand, five hundred twenty-one".