21133215 has 12 divisors (see below), whose sum is σ = 36630984. Its totient is φ = 11271024.

The previous prime is 21133213. The next prime is 21133219. The reversal of 21133215 is 51233112.

It is not a de Polignac number, because 21133215 - 2¹ = 21133213 is a prime.

It is a super-2 number, since 2×21133215² = 893225552472450, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21133213) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 234769 + ... + 234858.

It is an arithmetic number, because the mean of its divisors is an integer number (3052582).

Almost surely, 2^21133215 is an apocalyptic number.

21133215 is a deficient number, since it is larger than the sum of its proper divisors (15497769).

21133215 is a wasteful number, since it uses less digits than its factorization.

21133215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 469638 (or 469635 counting only the distinct ones).

The product of its digits is 180, while the sum is 18.

The square root of 21133215 is about 4597.0876650332. The cubic root of 21133215 is about 276.4745694799.

Adding to 21133215 its reverse (51233112), we get a palindrome (72366327).

The spelling of 21133215 in words is "twenty-one million, one hundred thirty-three thousand, two hundred fifteen".