81146993 has 2 divisors, whose sum is σ = 81146994. Its totient is φ = 81146992.

The previous prime is 81146971. The next prime is 81147041. The reversal of 81146993 is 39964118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66455104 + 14691889 = 8152^2 + 3833^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81146993 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81146993.

It is not a weakly prime, because it can be changed into another prime (81146893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40573496 + 40573497.

It is an arithmetic number, because the mean of its divisors is an integer number (40573497).

Almost surely, 2^81146993 is an apocalyptic number.

It is an amenable number.

81146993 is a deficient number, since it is larger than the sum of its proper divisors (1).

81146993 is an equidigital number, since it uses as much as digits as its factorization.

81146993 is an odious number, because the sum of its binary digits is odd.

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

The square root of 81146993 is about 9008.1625762416. The cubic root of 81146993 is about 432.9364420540.

The spelling of 81146993 in words is "eighty-one million, one hundred forty-six thousand, nine hundred ninety-three".