21233239 has 2 divisors, whose sum is σ = 21233240. Its totient is φ = 21233238.

The previous prime is 21233213. The next prime is 21233243. The reversal of 21233239 is 93233212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21233239 - 2⁷ = 21233111 is a prime.

It is a super-2 number, since 2×21233239² = 901700876862242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21233269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10616619 + 10616620.

It is an arithmetic number, because the mean of its divisors is an integer number (10616620).

Almost surely, 2^21233239 is an apocalyptic number.

21233239 is a deficient number, since it is larger than the sum of its proper divisors (1).

21233239 is an equidigital number, since it uses as much as digits as its factorization.

21233239 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1944, while the sum is 25.

The square root of 21233239 is about 4607.9538843179. The cubic root of 21233239 is about 276.9100699870.

The spelling of 21233239 in words is "twenty-one million, two hundred thirty-three thousand, two hundred thirty-nine".