21895155 has 12 divisors (see below), whose sum is σ = 37951680. Its totient is φ = 11677392.

The previous prime is 21895147. The next prime is 21895169. The reversal of 21895155 is 55159812.

It is a happy number.

It is not a de Polignac number, because 21895155 - 2³ = 21895147 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 243235 + ... + 243324.

It is an arithmetic number, because the mean of its divisors is an integer number (3162640).

Almost surely, 2^21895155 is an apocalyptic number.

21895155 is a deficient number, since it is larger than the sum of its proper divisors (16056525).

21895155 is a wasteful number, since it uses less digits than its factorization.

21895155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 486570 (or 486567 counting only the distinct ones).

The product of its digits is 18000, while the sum is 36.

The square root of 21895155 is about 4679.2258975177. The cubic root of 21895155 is about 279.7581031561.

The spelling of 21895155 in words is "twenty-one million, eight hundred ninety-five thousand, one hundred fifty-five".