81320377 has 2 divisors, whose sum is σ = 81320378. Its totient is φ = 81320376.

The previous prime is 81320363. The next prime is 81320417. The reversal of 81320377 is 77302318.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45846441 + 35473936 = 6771^2 + 5956^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81320377 is a prime.

It is a super-2 number, since 2×81320377² = 13226007430844258, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81320077) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40660188 + 40660189.

It is an arithmetic number, because the mean of its divisors is an integer number (40660189).

Almost surely, 2^81320377 is an apocalyptic number.

It is an amenable number.

81320377 is a deficient number, since it is larger than the sum of its proper divisors (1).

81320377 is an equidigital number, since it uses as much as digits as its factorization.

81320377 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7056, while the sum is 31.

The square root of 81320377 is about 9017.7811572471. The cubic root of 81320377 is about 433.2445695244.

The spelling of 81320377 in words is "eighty-one million, three hundred twenty thousand, three hundred seventy-seven".