20531391520 has 24 divisors (see below), whose sum is σ = 48505412844. Its totient is φ = 8212556544.

The previous prime is 20531391479. The next prime is 20531391539. The reversal of 20531391520 is 2519313502.

It can be written as a sum of positive squares in 2 ways, for example, as 19133528976 + 1397862544 = 138324^2 + 37388^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64160439 + ... + 64160758.

Almost surely, 2^20531391520 is an apocalyptic number.

20531391520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20531391520 is an abundant number, since it is smaller than the sum of its proper divisors (27974021324).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20531391520 is a wasteful number, since it uses less digits than its factorization.

20531391520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128321212 (or 128321204 counting only the distinct ones).

The product of its (nonzero) digits is 8100, while the sum is 31.

The spelling of 20531391520 in words is "twenty billion, five hundred thirty-one million, three hundred ninety-one thousand, five hundred twenty".