21233261 has 4 divisors (see below), whose sum is σ = 24266592. Its totient is φ = 18199932.

The previous prime is 21233243. The next prime is 21233263. The reversal of 21233261 is 16233212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21233261 - 2⁶ = 21233197 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21233263) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1516655 + ... + 1516668.

It is an arithmetic number, because the mean of its divisors is an integer number (6066648).

Almost surely, 2^21233261 is an apocalyptic number.

It is an amenable number.

21233261 is a deficient number, since it is larger than the sum of its proper divisors (3033331).

21233261 is an equidigital number, since it uses as much as digits as its factorization.

21233261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3033330.

The product of its digits is 432, while the sum is 20.

The square root of 21233261 is about 4607.9562714939. The cubic root of 21233261 is about 276.9101656235.

Adding to 21233261 its reverse (16233212), we get a palindrome (37466473).

The spelling of 21233261 in words is "twenty-one million, two hundred thirty-three thousand, two hundred sixty-one".