21838231 has 2 divisors, whose sum is σ = 21838232. Its totient is φ = 21838230.

The previous prime is 21838171. The next prime is 21838237. The reversal of 21838231 is 13283812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21838231 - 2¹⁵ = 21805463 is a prime.

It is a super-2 number, since 2×21838231² = 953816666418722, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21838231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21838237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10919115 + 10919116.

It is an arithmetic number, because the mean of its divisors is an integer number (10919116).

Almost surely, 2^21838231 is an apocalyptic number.

21838231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21838231 is an equidigital number, since it uses as much as digits as its factorization.

21838231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 28.

The square root of 21838231 is about 4673.1393088587. The cubic root of 21838231 is about 279.5154502187.

The spelling of 21838231 in words is "twenty-one million, eight hundred thirty-eight thousand, two hundred thirty-one".