81455431 has 2 divisors, whose sum is σ = 81455432. Its totient is φ = 81455430.

The previous prime is 81455417. The next prime is 81455441. The reversal of 81455431 is 13455418.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81455431 - 2⁷ = 81455303 is a prime.

It is a super-2 number, since 2×81455431² = 13269974478791522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81455393 and 81455402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81455401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40727715 + 40727716.

It is an arithmetic number, because the mean of its divisors is an integer number (40727716).

Almost surely, 2^81455431 is an apocalyptic number.

81455431 is a deficient number, since it is larger than the sum of its proper divisors (1).

81455431 is an equidigital number, since it uses as much as digits as its factorization.

81455431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9600, while the sum is 31.

The square root of 81455431 is about 9025.2662564602. The cubic root of 81455431 is about 433.4842759500.

The spelling of 81455431 in words is "eighty-one million, four hundred fifty-five thousand, four hundred thirty-one".