20531255540 has 48 divisors (see below), whose sum is σ = 43950165840. Its totient is φ = 8053693440.

The previous prime is 20531255533. The next prime is 20531255557. The reversal of 20531255540 is 4555213502.

It can be written as a sum of positive squares in 8 ways, for example, as 2499600016 + 18031655524 = 49996^2 + 134282^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20531255497 and 20531255506.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3368816 + ... + 3374904.

It is an arithmetic number, because the mean of its divisors is an integer number (915628455).

Almost surely, 2^20531255540 is an apocalyptic number.

20531255540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20531255540 is an abundant number, since it is smaller than the sum of its proper divisors (23418910300).

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

20531255540 is a wasteful number, since it uses less digits than its factorization.

20531255540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9332 (or 9330 counting only the distinct ones).

The product of its (nonzero) digits is 30000, while the sum is 32.

The spelling of 20531255540 in words is "twenty billion, five hundred thirty-one million, two hundred fifty-five thousand, five hundred forty".