21292231 has 2 divisors, whose sum is σ = 21292232. Its totient is φ = 21292230.

The previous prime is 21292189. The next prime is 21292241. The reversal of 21292231 is 13229212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21292231 - 2⁹ = 21291719 is a prime.

It is a super-2 number, since 2×21292231² = 906718201914722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21292241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10646115 + 10646116.

It is an arithmetic number, because the mean of its divisors is an integer number (10646116).

Almost surely, 2^21292231 is an apocalyptic number.

21292231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21292231 is an equidigital number, since it uses as much as digits as its factorization.

21292231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 22.

The square root of 21292231 is about 4614.3505501858. The cubic root of 21292231 is about 277.1662779376.

The spelling of 21292231 in words is "twenty-one million, two hundred ninety-two thousand, two hundred thirty-one".