20662512021 has 20 divisors (see below), whose sum is σ = 30939589164. Its totient is φ = 13742265600.

The previous prime is 20662512007. The next prime is 20662512043. The reversal of 20662512021 is 12021526602.

20662512021 is a `hidden beast` number, since 2 + 0 + 6 + 625 + 12 + 0 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 671379921 + 19991132100 = 25911^2 + 141390^2 .

It is not a de Polignac number, because 20662512021 - 2³⁰ = 19588770197 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20662512121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 268860 + ... + 337061.

Almost surely, 2^20662512021 is an apocalyptic number.

It is an amenable number.

20662512021 is a deficient number, since it is larger than the sum of its proper divisors (10277077143).

20662512021 is an equidigital number, since it uses as much as digits as its factorization.

20662512021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 606354 (or 606345 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The spelling of 20662512021 in words is "twenty billion, six hundred sixty-two million, five hundred twelve thousand, twenty-one".