20923939517 has 24 divisors (see below), whose sum is σ = 22848202944. Its totient is φ = 19152267264.

The previous prime is 20923939513. The next prime is 20923939579. The reversal of 20923939517 is 71593932902.

It is not a de Polignac number, because 20923939517 - 2² = 20923939513 is a prime.

It is a super-2 number, since 2×20923939517² (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 (20923939513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18146813 + ... + 18147965.

It is an arithmetic number, because the mean of its divisors is an integer number (952008456).

Almost surely, 2^20923939517 is an apocalyptic number.

It is an amenable number.

20923939517 is a deficient number, since it is larger than the sum of its proper divisors (1924263427).

20923939517 is a wasteful number, since it uses less digits than its factorization.

20923939517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1989 (or 1976 counting only the distinct ones).

The product of its (nonzero) digits is 918540, while the sum is 50.

The spelling of 20923939517 in words is "twenty billion, nine hundred twenty-three million, nine hundred thirty-nine thousand, five hundred seventeen".