21422231 has 2 divisors, whose sum is σ = 21422232. Its totient is φ = 21422230.

The previous prime is 21422221. The next prime is 21422273. The reversal of 21422231 is 13222412.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21422231 is a prime.

It is a super-2 number, since 2×21422231² = 917823962034722, 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 (21422221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10711115 + 10711116.

It is an arithmetic number, because the mean of its divisors is an integer number (10711116).

Almost surely, 2^21422231 is an apocalyptic number.

21422231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21422231 is an equidigital number, since it uses as much as digits as its factorization.

21422231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 192, while the sum is 17.

The square root of 21422231 is about 4628.4156036380. The cubic root of 21422231 is about 277.7292146155.

Adding to 21422231 its reverse (13222412), we get a palindrome (34644643).

The spelling of 21422231 in words is "twenty-one million, four hundred twenty-two thousand, two hundred thirty-one".