81320807 has 2 divisors, whose sum is σ = 81320808. Its totient is φ = 81320806.

The previous prime is 81320803. The next prime is 81320873. The reversal of 81320807 is 70802318.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81320807 - 2² = 81320803 is a prime.

It is a super-2 number, since 2×81320807² = 13226147302262498, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81320807.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81320803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40660403 + 40660404.

It is an arithmetic number, because the mean of its divisors is an integer number (40660404).

Almost surely, 2^81320807 is an apocalyptic number.

81320807 is a deficient number, since it is larger than the sum of its proper divisors (1).

81320807 is an equidigital number, since it uses as much as digits as its factorization.

81320807 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 81320807 is about 9017.8049990006. The cubic root of 81320807 is about 433.2453331494.

The spelling of 81320807 in words is "eighty-one million, three hundred twenty thousand, eight hundred seven".