20513511540 has 36 divisors (see below), whose sum is σ = 62224318884. Its totient is φ = 5470269696.

The previous prime is 20513511523. The next prime is 20513511541. The reversal of 20513511540 is 4511531502.

20513511540 is a `hidden beast` number, since 20 + 51 + 3 + 51 + 1 + 540 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 7895033316 + 12618478224 = 88854^2 + 112332^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20513511541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 56981797 + ... + 56982156.

Almost surely, 2^20513511540 is an apocalyptic number.

20513511540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20513511540 is an abundant number, since it is smaller than the sum of its proper divisors (41710807344).

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

20513511540 is a wasteful number, since it uses less digits than its factorization.

20513511540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113963968 (or 113963963 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

The spelling of 20513511540 in words is "twenty billion, five hundred thirteen million, five hundred eleven thousand, five hundred forty".