20515551431553 has 12 divisors (see below), whose sum is σ = 30589496041728. Its totient is φ = 13235839633080.

The previous prime is 20515551431539. The next prime is 20515551431581. The reversal of 20515551431553 is 35513415551502.

20515551431553 is a `hidden beast` number, since 2 + 0 + 5 + 1 + 5 + 5 + 51 + 43 + 1 + 553 = 666.

It is not a de Polignac number, because 20515551431553 - 2²⁴ = 20515534654337 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20515551431499 and 20515551431508.

It is not an unprimeable number, because it can be changed into a prime (20515551431513) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 36766220925 + ... + 36766221482.

It is an arithmetic number, because the mean of its divisors is an integer number (2549124670144).

Almost surely, 2^{20515551431553} is an apocalyptic number.

It is an amenable number.

20515551431553 is a deficient number, since it is larger than the sum of its proper divisors (10073944610175).

20515551431553 is a wasteful number, since it uses less digits than its factorization.

20515551431553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73532442444 (or 73532442441 counting only the distinct ones).

The product of its (nonzero) digits is 1125000, while the sum is 45.

The spelling of 20515551431553 in words is "twenty trillion, five hundred fifteen billion, five hundred fifty-one million, four hundred thirty-one thousand, five hundred fifty-three".