20518991539 has 8 divisors (see below), whose sum is σ = 20574259200. Its totient is φ = 20463760200.

The previous prime is 20518991509. The next prime is 20518991567. The reversal of 20518991539 is 93519981502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20518991539 - 2¹³ = 20518983347 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20518991509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1414654 + ... + 1429084.

It is an arithmetic number, because the mean of its divisors is an integer number (2571782400).

Almost surely, 2^20518991539 is an apocalyptic number.

20518991539 is a deficient number, since it is larger than the sum of its proper divisors (55267661).

20518991539 is a wasteful number, since it uses less digits than its factorization.

20518991539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18161.

The product of its (nonzero) digits is 874800, while the sum is 52.

The spelling of 20518991539 in words is "twenty billion, five hundred eighteen million, nine hundred ninety-one thousand, five hundred thirty-nine".