215561105520 has 40 divisors (see below), whose sum is σ = 668239427856. Its totient is φ = 57482961408.

The previous prime is 215561105509. The next prime is 215561105579. The reversal of 215561105520 is 25501165512.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 449085397 + ... + 449085876.

Almost surely, 2^215561105520 is an apocalyptic number.

215561105520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

215561105520 is an abundant number, since it is smaller than the sum of its proper divisors (452678322336).

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

215561105520 is a wasteful number, since it uses less digits than its factorization.

215561105520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 898171289 (or 898171283 counting only the distinct ones).

The product of its (nonzero) digits is 15000, while the sum is 33.

The spelling of 215561105520 in words is "two hundred fifteen billion, five hundred sixty-one million, one hundred five thousand, five hundred twenty".