21155165215100 has 72 divisors (see below), whose sum is σ = 52473053155488. Its totient is φ = 7252059859200.

The previous prime is 21155165215099. The next prime is 21155165215133. The reversal of 21155165215100 is 151256155112.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2090030 + ... + 6832170.

Almost surely, 2^{21155165215100} is an apocalyptic number.

21155165215100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21155165215100 is an abundant number, since it is smaller than the sum of its proper divisors (31317887940388).

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

21155165215100 is a wasteful number, since it uses less digits than its factorization.

21155165215100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4748535 (or 4748528 counting only the distinct ones).

The product of its (nonzero) digits is 15000, while the sum is 35.

The spelling of 21155165215100 in words is "twenty-one trillion, one hundred fifty-five billion, one hundred sixty-five million, two hundred fifteen thousand, one hundred".