21379255 has 4 divisors (see below), whose sum is σ = 25655112. Its totient is φ = 17103400.

The previous prime is 21379249. The next prime is 21379271. The reversal of 21379255 is 55297312.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21379255 - 2²³ = 12990647 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21379255.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2137921 + ... + 2137930.

It is an arithmetic number, because the mean of its divisors is an integer number (6413778).

Almost surely, 2^21379255 is an apocalyptic number.

21379255 is a deficient number, since it is larger than the sum of its proper divisors (4275857).

21379255 is an equidigital number, since it uses as much as digits as its factorization.

21379255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4275856.

The product of its digits is 18900, while the sum is 34.

The square root of 21379255 is about 4623.7706474262. The cubic root of 21379255 is about 277.5433690300.

The spelling of 21379255 in words is "twenty-one million, three hundred seventy-nine thousand, two hundred fifty-five".