81368999 has 2 divisors, whose sum is σ = 81369000. Its totient is φ = 81368998.

The previous prime is 81368977. The next prime is 81369019. The reversal of 81368999 is 99986318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81368999 - 2⁸ = 81368743 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81368999.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81368699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40684499 + 40684500.

It is an arithmetic number, because the mean of its divisors is an integer number (40684500).

Almost surely, 2^81368999 is an apocalyptic number.

81368999 is a deficient number, since it is larger than the sum of its proper divisors (1).

81368999 is an equidigital number, since it uses as much as digits as its factorization.

81368999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 839808, while the sum is 53.

The square root of 81368999 is about 9020.4766503772. The cubic root of 81368999 is about 433.3308989344.

The spelling of 81368999 in words is "eighty-one million, three hundred sixty-eight thousand, nine hundred ninety-nine".