81264431 has 2 divisors, whose sum is σ = 81264432. Its totient is φ = 81264430.

The previous prime is 81264397. The next prime is 81264433. The reversal of 81264431 is 13446218.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81264431 is a prime.

It is a super-2 number, since 2×81264431² = 13207815491507522, which contains 22 as substring.

Together with 81264433, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 81264394 and 81264403.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81264433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40632215 + 40632216.

It is an arithmetic number, because the mean of its divisors is an integer number (40632216).

Almost surely, 2^81264431 is an apocalyptic number.

81264431 is a deficient number, since it is larger than the sum of its proper divisors (1).

81264431 is an equidigital number, since it uses as much as digits as its factorization.

81264431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4608, while the sum is 29.

The square root of 81264431 is about 9014.6786409722. The cubic root of 81264431 is about 433.1451936069.

The spelling of 81264431 in words is "eighty-one million, two hundred sixty-four thousand, four hundred thirty-one".