20564142621 has 16 divisors (see below), whose sum is σ = 29918756160. Its totient is φ = 12460085120.

The previous prime is 20564142593. The next prime is 20564142649. The reversal of 20564142621 is 12624146502.

It is an interprime number because it is at equal distance from previous prime (20564142593) and next prime (20564142649).

It is a cyclic number.

It is not a de Polignac number, because 20564142621 - 2²⁶ = 20497033757 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20564142661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 65881 + ... + 213233.

It is an arithmetic number, because the mean of its divisors is an integer number (1869922260).

Almost surely, 2^20564142621 is an apocalyptic number.

It is an amenable number.

20564142621 is a deficient number, since it is larger than the sum of its proper divisors (9354613539).

20564142621 is a wasteful number, since it uses less digits than its factorization.

20564142621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151596.

The product of its (nonzero) digits is 23040, while the sum is 33.

The spelling of 20564142621 in words is "twenty billion, five hundred sixty-four million, one hundred forty-two thousand, six hundred twenty-one".