81431207593 has 2 divisors, whose sum is σ = 81431207594. Its totient is φ = 81431207592.

The previous prime is 81431207579. The next prime is 81431207617. The reversal of 81431207593 is 39570213418.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80594667664 + 836539929 = 283892^2 + 28923^2 .

It is a cyclic number.

It is not a de Polignac number, because 81431207593 - 2¹⁷ = 81431076521 is a prime.

It is not a weakly prime, because it can be changed into another prime (81431207573) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40715603796 + 40715603797.

It is an arithmetic number, because the mean of its divisors is an integer number (40715603797).

Almost surely, 2^81431207593 is an apocalyptic number.

It is an amenable number.

81431207593 is a deficient number, since it is larger than the sum of its proper divisors (1).

81431207593 is an equidigital number, since it uses as much as digits as its factorization.

81431207593 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181440, while the sum is 43.

The spelling of 81431207593 in words is "eighty-one billion, four hundred thirty-one million, two hundred seven thousand, five hundred ninety-three".