21132331 has 16 divisors (see below), whose sum is σ = 24323328. Its totient is φ = 18172000.

The previous prime is 21132317. The next prime is 21132341. The reversal of 21132331 is 13323112.

It is not a de Polignac number, because 21132331 - 2¹⁵ = 21099563 is a prime.

It is a super-2 number, since 2×21132331² = 893150826987122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21132301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25140 + ... + 25966.

It is an arithmetic number, because the mean of its divisors is an integer number (1520208).

Almost surely, 2^21132331 is an apocalyptic number.

21132331 is a deficient number, since it is larger than the sum of its proper divisors (3190997).

21132331 is a wasteful number, since it uses less digits than its factorization.

21132331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 962.

The product of its digits is 108, while the sum is 16.

The square root of 21132331 is about 4596.9915161984. The cubic root of 21132331 is about 276.4707144595.

Adding to 21132331 its reverse (13323112), we get a palindrome (34455443).

It can be divided in two parts, 2113 and 2331, that added together give a palindrome (4444).

The spelling of 21132331 in words is "twenty-one million, one hundred thirty-two thousand, three hundred thirty-one".