21551355513 has 12 divisors (see below), whose sum is σ = 31792071168. Its totient is φ = 14061877080.

The previous prime is 21551355503. The next prime is 21551355521. The reversal of 21551355513 is 31555315512.

21551355513 is a `hidden beast` number, since 2 + 1 + 5 + 5 + 135 + 5 + 513 = 666.

It is not a de Polignac number, because 21551355513 - 2³² = 17256388217 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21551355503) 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, 25473993 + ... + 25474838.

It is an arithmetic number, because the mean of its divisors is an integer number (2649339264).

Almost surely, 2^21551355513 is an apocalyptic number.

It is an amenable number.

21551355513 is a deficient number, since it is larger than the sum of its proper divisors (10240715655).

21551355513 is a wasteful number, since it uses less digits than its factorization.

21551355513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50948884 (or 50948881 counting only the distinct ones).

The product of its digits is 56250, while the sum is 36.

The spelling of 21551355513 in words is "twenty-one billion, five hundred fifty-one million, three hundred fifty-five thousand, five hundred thirteen".