20865968731 has 4 divisors (see below), whose sum is σ = 20971887552. Its totient is φ = 20760049912.

The previous prime is 20865968699. The next prime is 20865968771. The reversal of 20865968731 is 13786956802.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20865968731 - 2⁵ = 20865968699 is a prime.

It is a super-2 number, since 2×20865968731² (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 (20865968771) 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, 52959115 + ... + 52959508.

It is an arithmetic number, because the mean of its divisors is an integer number (5242971888).

Almost surely, 2^20865968731 is an apocalyptic number.

20865968731 is a deficient number, since it is larger than the sum of its proper divisors (105918821).

20865968731 is a wasteful number, since it uses less digits than its factorization.

20865968731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105918820.

The product of its (nonzero) digits is 4354560, while the sum is 55.

The spelling of 20865968731 in words is "twenty billion, eight hundred sixty-five million, nine hundred sixty-eight thousand, seven hundred thirty-one".