21233231 has 6 divisors (see below), whose sum is σ = 21644280. Its totient is φ = 20829848.

The previous prime is 21233213. The next prime is 21233239. The reversal of 21233231 is 13233212.

It is not a de Polignac number, because 21233231 - 2¹⁰ = 21232207 is a prime.

It is a super-2 number, since 2×21233231² = 901700197398722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21233239) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 971 + ... + 6588.

It is an arithmetic number, because the mean of its divisors is an integer number (3607380).

Almost surely, 2^21233231 is an apocalyptic number.

21233231 is a deficient number, since it is larger than the sum of its proper divisors (411049).

21233231 is an frugal number, since it uses more digits than its factorization.

21233231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7665 (or 7612 counting only the distinct ones).

The product of its digits is 216, while the sum is 17.

The square root of 21233231 is about 4607.9530162535. The cubic root of 21233231 is about 276.9100352100.

Adding to 21233231 its reverse (13233212), we get a palindrome (34466443).

The spelling of 21233231 in words is "twenty-one million, two hundred thirty-three thousand, two hundred thirty-one".