20566714921 has 9 divisors (see below), whose sum is σ = 20918298999. Its totient is φ = 20220951000.

The previous prime is 20566714907. The next prime is 20566714967. The reversal of 20566714921 is 12941766502.

The square root of 20566714921 is 143411.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 668791321 + 19897923600 = 25861^2 + 141060^2 .

It is not a de Polignac number, because 20566714921 - 2¹³ = 20566706729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20566714981) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 8746896 + ... + 8749246.

Almost surely, 2^20566714921 is an apocalyptic number.

20566714921 is the 143411-st square number.

20566714921 is the 71706-th centered octagonal number.

It is an amenable number.

20566714921 is a deficient number, since it is larger than the sum of its proper divisors (351584078).

20566714921 is an frugal number, since it uses more digits than its factorization.

20566714921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4824 (or 2412 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 43.

The spelling of 20566714921 in words is "twenty billion, five hundred sixty-six million, seven hundred fourteen thousand, nine hundred twenty-one".