21050231 has 2 divisors, whose sum is σ = 21050232. Its totient is φ = 21050230.

The previous prime is 21050203. The next prime is 21050251. The reversal of 21050231 is 13205012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21050231 is a prime.

It is a super-2 number, since 2×21050231² = 886224450306722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21050251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10525115 + 10525116.

It is an arithmetic number, because the mean of its divisors is an integer number (10525116).

Almost surely, 2^21050231 is an apocalyptic number.

21050231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21050231 is an equidigital number, since it uses as much as digits as its factorization.

21050231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 21050231 is about 4588.0530729276. The cubic root of 21050231 is about 276.1122163236.

Adding to 21050231 its reverse (13205012), we get a palindrome (34255243).

The spelling of 21050231 in words is "twenty-one million, fifty thousand, two hundred thirty-one".