21233391 has 16 divisors (see below), whose sum is σ = 30127104. Its totient is φ = 13256064.

The previous prime is 21233389. The next prime is 21233411. The reversal of 21233391 is 19333212.

It is not a de Polignac number, because 21233391 - 2¹ = 21233389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21233321) 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, 10440 + ... + 12306.

It is an arithmetic number, because the mean of its divisors is an integer number (1882944).

Almost surely, 2^21233391 is an apocalyptic number.

21233391 is a deficient number, since it is larger than the sum of its proper divisors (8893713).

21233391 is a wasteful number, since it uses less digits than its factorization.

21233391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2110.

The product of its digits is 972, while the sum is 24.

The square root of 21233391 is about 4607.9703775090. The cubic root of 21233391 is about 276.9107307471.

The spelling of 21233391 in words is "twenty-one million, two hundred thirty-three thousand, three hundred ninety-one".