21912255 has 48 divisors (see below), whose sum is σ = 40553760. Its totient is φ = 11225088.

The previous prime is 21912229. The next prime is 21912259. The reversal of 21912255 is 55221912.

It is not a de Polignac number, because 21912255 - 2¹⁰ = 21911231 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21912259) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 113439 + ... + 113631.

It is an arithmetic number, because the mean of its divisors is an integer number (844870).

Almost surely, 2^21912255 is an apocalyptic number.

21912255 is a deficient number, since it is larger than the sum of its proper divisors (18641505).

21912255 is a wasteful number, since it uses less digits than its factorization.

21912255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265 (or 230 counting only the distinct ones).

The product of its digits is 1800, while the sum is 27.

The square root of 21912255 is about 4681.0527662055. The cubic root of 21912255 is about 279.8309140697.

The spelling of 21912255 in words is "twenty-one million, nine hundred twelve thousand, two hundred fifty-five".