81275431 has 2 divisors, whose sum is σ = 81275432. Its totient is φ = 81275430.

The previous prime is 81275377. The next prime is 81275443. The reversal of 81275431 is 13457218.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81275431 - 2⁷ = 81275303 is a prime.

It is a super-2 number, since 2×81275431² = 13211391368471522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81275393 and 81275402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81275231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40637715 + 40637716.

It is an arithmetic number, because the mean of its divisors is an integer number (40637716).

Almost surely, 2^81275431 is an apocalyptic number.

81275431 is a deficient number, since it is larger than the sum of its proper divisors (1).

81275431 is an equidigital number, since it uses as much as digits as its factorization.

81275431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6720, while the sum is 31.

The square root of 81275431 is about 9015.2887363634. The cubic root of 81275431 is about 433.1647363191.

The spelling of 81275431 in words is "eighty-one million, two hundred seventy-five thousand, four hundred thirty-one".