81331351 has 2 divisors, whose sum is σ = 81331352. Its totient is φ = 81331350.

The previous prime is 81331339. The next prime is 81331357. The reversal of 81331351 is 15313318.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81331351 is a prime.

It is a super-2 number, since 2×81331351² = 13229577310970402, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81331357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40665675 + 40665676.

It is an arithmetic number, because the mean of its divisors is an integer number (40665676).

Almost surely, 2^81331351 is an apocalyptic number.

81331351 is a deficient number, since it is larger than the sum of its proper divisors (1).

81331351 is an equidigital number, since it uses as much as digits as its factorization.

81331351 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1080, while the sum is 25.

The square root of 81331351 is about 9018.3896012537. The cubic root of 81331351 is about 433.2640571044.

Adding to 81331351 its reverse (15313318), we get a palindrome (96644669).

The spelling of 81331351 in words is "eighty-one million, three hundred thirty-one thousand, three hundred fifty-one".