21355515156 has 24 divisors (see below), whose sum is σ = 50674105440. Its totient is φ = 6997852192.

The previous prime is 21355515149. The next prime is 21355515163. The reversal of 21355515156 is 65151555312.

It is an interprime number because it is at equal distance from previous prime (21355515149) and next prime (21355515163).

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 15080871 + ... + 15082286.

It is an arithmetic number, because the mean of its divisors is an integer number (2111421060).

Almost surely, 2^21355515156 is an apocalyptic number.

It is an amenable number.

21355515156 is an abundant number, since it is smaller than the sum of its proper divisors (29318590284).

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

21355515156 is a wasteful number, since it uses less digits than its factorization.

21355515156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30163223 (or 30163221 counting only the distinct ones).

The product of its digits is 112500, while the sum is 39.

The spelling of 21355515156 in words is "twenty-one billion, three hundred fifty-five million, five hundred fifteen thousand, one hundred fifty-six".