20937323581 has 4 divisors (see below), whose sum is σ = 22039288000. Its totient is φ = 19835359164.

The previous prime is 20937323521. The next prime is 20937323611. The reversal of 20937323581 is 18532373902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20937323581 - 2¹⁷ = 20937192509 is a prime.

It is a super-2 number, since 2×20937323581² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20937323521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 550982181 + ... + 550982218.

It is an arithmetic number, because the mean of its divisors is an integer number (5509822000).

Almost surely, 2^20937323581 is an apocalyptic number.

It is an amenable number.

20937323581 is a deficient number, since it is larger than the sum of its proper divisors (1101964419).

20937323581 is a wasteful number, since it uses less digits than its factorization.

20937323581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1101964418.

The product of its (nonzero) digits is 272160, while the sum is 43.

The spelling of 20937323581 in words is "twenty billion, nine hundred thirty-seven million, three hundred twenty-three thousand, five hundred eighty-one".