21268231 has 2 divisors, whose sum is σ = 21268232. Its totient is φ = 21268230.

The previous prime is 21268213. The next prime is 21268249. The reversal of 21268231 is 13286212.

Together with previous prime (21268213) it forms an Ormiston pair, because they use the same digits, order apart.

It is a balanced prime because it is at equal distance from previous prime (21268213) and next prime (21268249).

It is a cyclic number.

It is not a de Polignac number, because 21268231 - 2⁷ = 21268103 is a prime.

It is a super-2 number, since 2×21268231² = 904675299738722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21268196 and 21268205.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21268271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10634115 + 10634116.

It is an arithmetic number, because the mean of its divisors is an integer number (10634116).

Almost surely, 2^21268231 is an apocalyptic number.

21268231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21268231 is an equidigital number, since it uses as much as digits as its factorization.

21268231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 25.

The square root of 21268231 is about 4611.7492342928. The cubic root of 21268231 is about 277.0621007920.

The spelling of 21268231 in words is "twenty-one million, two hundred sixty-eight thousand, two hundred thirty-one".