81087079391 has 2 divisors, whose sum is σ = 81087079392. Its totient is φ = 81087079390.

The previous prime is 81087079387. The next prime is 81087079421. The reversal of 81087079391 is 19397078018.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81087079391 - 2² = 81087079387 is a prime.

It is a super-2 number, since 2×81087079391² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81087079321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40543539695 + 40543539696.

It is an arithmetic number, because the mean of its divisors is an integer number (40543539696).

Almost surely, 2^81087079391 is an apocalyptic number.

81087079391 is a deficient number, since it is larger than the sum of its proper divisors (1).

81087079391 is an equidigital number, since it uses as much as digits as its factorization.

81087079391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 762048, while the sum is 53.

The spelling of 81087079391 in words is "eighty-one billion, eighty-seven million, seventy-nine thousand, three hundred ninety-one".