21133211 has 16 divisors (see below), whose sum is σ = 23708160. Its totient is φ = 18676320.

The previous prime is 21133153. The next prime is 21133213. The reversal of 21133211 is 11233112.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21133211 is a prime.

It is a super-2 number, since 2×21133211² = 893225214341042, which contains 22 as substring.

It is a Duffinian 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 15 ways as a sum of consecutive naturals, for example, 71981 + ... + 72273.

It is an arithmetic number, because the mean of its divisors is an integer number (1481760).

Almost surely, 2^21133211 is an apocalyptic number.

21133211 is a deficient number, since it is larger than the sum of its proper divisors (2574949).

21133211 is a wasteful number, since it uses less digits than its factorization.

21133211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 466.

The product of its digits is 36, while the sum is 14.

The square root of 21133211 is about 4597.0872299751. The cubic root of 21133211 is about 276.4745520367.

Adding to 21133211 its reverse (11233112), we get a palindrome (32366323).

Subtracting from 21133211 its reverse (11233112), we obtain a palindrome (9900099).

The spelling of 21133211 in words is "twenty-one million, one hundred thirty-three thousand, two hundred eleven".