81153431 has 2 divisors, whose sum is σ = 81153432. Its totient is φ = 81153430.

The previous prime is 81153419. The next prime is 81153437. The reversal of 81153431 is 13435118.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81153431 - 2⁶ = 81153367 is a prime.

It is a super-2 number, since 2×81153431² = 13171758726143522, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81153431.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81153437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40576715 + 40576716.

It is an arithmetic number, because the mean of its divisors is an integer number (40576716).

Almost surely, 2^81153431 is an apocalyptic number.

81153431 is a deficient number, since it is larger than the sum of its proper divisors (1).

81153431 is an equidigital number, since it uses as much as digits as its factorization.

81153431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 26.

The square root of 81153431 is about 9008.5199117280. The cubic root of 81153431 is about 432.9478911170.

Adding to 81153431 its reverse (13435118), we get a palindrome (94588549).

The spelling of 81153431 in words is "eighty-one million, one hundred fifty-three thousand, four hundred thirty-one".