81232231 has 2 divisors, whose sum is σ = 81232232. Its totient is φ = 81232230.

The previous prime is 81232223. The next prime is 81232237. The reversal of 81232231 is 13223218.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81232231 - 2³ = 81232223 is a prime.

It is a super-2 number, since 2×81232231² = 13197350706474722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81232237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40616115 + 40616116.

It is an arithmetic number, because the mean of its divisors is an integer number (40616116).

Almost surely, 2^81232231 is an apocalyptic number.

81232231 is a deficient number, since it is larger than the sum of its proper divisors (1).

81232231 is an equidigital number, since it uses as much as digits as its factorization.

81232231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576, while the sum is 22.

The square root of 81232231 is about 9012.8924879863. The cubic root of 81232231 is about 433.0879766194.

Adding to 81232231 its reverse (13223218), we get a palindrome (94455449).

The spelling of 81232231 in words is "eighty-one million, two hundred thirty-two thousand, two hundred thirty-one".