81312526879 has 2 divisors, whose sum is σ = 81312526880. Its totient is φ = 81312526878.

The previous prime is 81312526877. The next prime is 81312526907. The reversal of 81312526879 is 97862521318.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81312526879 - 2¹ = 81312526877 is a prime.

It is a super-2 number, since 2×81312526879² (a number of 23 digits) contains 22 as substring.

Together with 81312526877, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81312526877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40656263439 + 40656263440.

It is an arithmetic number, because the mean of its divisors is an integer number (40656263440).

Almost surely, 2^81312526879 is an apocalyptic number.

81312526879 is a deficient number, since it is larger than the sum of its proper divisors (1).

81312526879 is an equidigital number, since it uses as much as digits as its factorization.

81312526879 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1451520, while the sum is 52.

The spelling of 81312526879 in words is "eighty-one billion, three hundred twelve million, five hundred twenty-six thousand, eight hundred seventy-nine".