81401431 has 2 divisors, whose sum is σ = 81401432. Its totient is φ = 81401430.

The previous prime is 81401413. The next prime is 81401459. The reversal of 81401431 is 13410418.

Together with previous prime (81401413) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81401431 - 2⁵ = 81401399 is a prime.

It is a super-2 number, since 2×81401431² = 13252385937695522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81401461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40700715 + 40700716.

It is an arithmetic number, because the mean of its divisors is an integer number (40700716).

Almost surely, 2^81401431 is an apocalyptic number.

81401431 is a deficient number, since it is larger than the sum of its proper divisors (1).

81401431 is an equidigital number, since it uses as much as digits as its factorization.

81401431 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 81401431 is about 9022.2741589912. The cubic root of 81401431 is about 433.3884635315.

Adding to 81401431 its reverse (13410418), we get a palindrome (94811849).

The spelling of 81401431 in words is "eighty-one million, four hundred one thousand, four hundred thirty-one".