81015225913 has 2 divisors, whose sum is σ = 81015225914. Its totient is φ = 81015225912.

The previous prime is 81015225911. The next prime is 81015225919. The reversal of 81015225913 is 31952251018.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 79847500329 + 1167725584 = 282573^2 + 34172^2 .

It is a cyclic number.

It is not a de Polignac number, because 81015225913 - 2¹ = 81015225911 is a prime.

Together with 81015225911, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (81015225911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40507612956 + 40507612957.

It is an arithmetic number, because the mean of its divisors is an integer number (40507612957).

Almost surely, 2^81015225913 is an apocalyptic number.

It is an amenable number.

81015225913 is a deficient number, since it is larger than the sum of its proper divisors (1).

81015225913 is an equidigital number, since it uses as much as digits as its factorization.

81015225913 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21600, while the sum is 37.

The spelling of 81015225913 in words is "eighty-one billion, fifteen million, two hundred twenty-five thousand, nine hundred thirteen".