21153315 has 16 divisors (see below), whose sum is σ = 34937856. Its totient is φ = 10917600.

The previous prime is 21153299. The next prime is 21153323. The reversal of 21153315 is 51335112.

It is not a de Polignac number, because 21153315 - 2⁴ = 21153299 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21153291 and 21153300.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22281 + ... + 23210.

It is an arithmetic number, because the mean of its divisors is an integer number (2183616).

Almost surely, 2^21153315 is an apocalyptic number.

21153315 is a deficient number, since it is larger than the sum of its proper divisors (13784541).

21153315 is a wasteful number, since it uses less digits than its factorization.

21153315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45530.

The product of its digits is 450, while the sum is 21.

The square root of 21153315 is about 4599.2733121657. The cubic root of 21153315 is about 276.5621942287.

Adding to 21153315 its reverse (51335112), we get a palindrome (72488427).

The spelling of 21153315 in words is "twenty-one million, one hundred fifty-three thousand, three hundred fifteen".