21881315 has 8 divisors (see below), whose sum is σ = 26753328. Its totient is φ = 17174560.

The previous prime is 21881297. The next prime is 21881351. The reversal of 21881315 is 51318812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21881315 - 2⁸ = 21881059 is a prime.

It is a super-2 number, since 2×21881315² = 957583892258450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41021 + ... + 41550.

It is an arithmetic number, because the mean of its divisors is an integer number (3344166).

Almost surely, 2^21881315 is an apocalyptic number.

21881315 is a deficient number, since it is larger than the sum of its proper divisors (4872013).

21881315 is an equidigital number, since it uses as much as digits as its factorization.

21881315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82629.

The product of its digits is 1920, while the sum is 29.

The square root of 21881315 is about 4677.7467866485. The cubic root of 21881315 is about 279.6991453907.

The spelling of 21881315 in words is "twenty-one million, eight hundred eighty-one thousand, three hundred fifteen".