21555126 has 32 divisors (see below), whose sum is σ = 49019520. Its totient is φ = 7017192.

The previous prime is 21555113. The next prime is 21555179. The reversal of 21555126 is 62155512.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 21555126.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2320 + ... + 6963.

It is an arithmetic number, because the mean of its divisors is an integer number (1531860).

Almost surely, 2^21555126 is an apocalyptic number.

21555126 is an abundant number, since it is smaller than the sum of its proper divisors (27464394).

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

21555126 is a wasteful number, since it uses less digits than its factorization.

21555126 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9337 (or 9331 counting only the distinct ones).

The product of its digits is 3000, while the sum is 27.

The square root of 21555126 is about 4642.7498317269. The cubic root of 21555126 is about 278.3023382922.

The spelling of 21555126 in words is "twenty-one million, five hundred fifty-five thousand, one hundred twenty-six".