21879315 has 40 divisors (see below), whose sum is σ = 39726720. Its totient is φ = 11518848.

The previous prime is 21879313. The next prime is 21879329. The reversal of 21879315 is 51397812.

It is not a de Polignac number, because 21879315 - 2¹ = 21879313 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21879315.

It is not an unprimeable number, because it can be changed into a prime (21879313) by changing a digit.

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 39 ways as a sum of consecutive naturals, for example, 35742 + ... + 36348.

It is an arithmetic number, because the mean of its divisors is an integer number (993168).

Almost surely, 2^21879315 is an apocalyptic number.

21879315 is a deficient number, since it is larger than the sum of its proper divisors (17847405).

21879315 is an equidigital number, since it uses as much as digits as its factorization.

21879315 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 713 (or 704 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 21879315 is about 4677.5330036249. The cubic root of 21879315 is about 279.6906234267.

The spelling of 21879315 in words is "twenty-one million, eight hundred seventy-nine thousand, three hundred fifteen".