81361499 has 2 divisors, whose sum is σ = 81361500. Its totient is φ = 81361498.

The previous prime is 81361487. The next prime is 81361513. The reversal of 81361499 is 99416318.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81361499 - 2²⁰ = 80312923 is a prime.

It is not a weakly prime, because it can be changed into another prime (81361799) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40680749 + 40680750.

It is an arithmetic number, because the mean of its divisors is an integer number (40680750).

Almost surely, 2^81361499 is an apocalyptic number.

81361499 is a deficient number, since it is larger than the sum of its proper divisors (1).

81361499 is an equidigital number, since it uses as much as digits as its factorization.

81361499 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46656, while the sum is 41.

The square root of 81361499 is about 9020.0609199717. The cubic root of 81361499 is about 433.3175847663.

The spelling of 81361499 in words is "eighty-one million, three hundred sixty-one thousand, four hundred ninety-nine".