81213057307 has 2 divisors, whose sum is σ = 81213057308. Its totient is φ = 81213057306.

The previous prime is 81213057269. The next prime is 81213057347. The reversal of 81213057307 is 70375031218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81213057307 - 2⁷ = 81213057179 is a prime.

It is not a weakly prime, because it can be changed into another prime (81213057347) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40606528653 + 40606528654.

It is an arithmetic number, because the mean of its divisors is an integer number (40606528654).

Almost surely, 2^81213057307 is an apocalyptic number.

81213057307 is a deficient number, since it is larger than the sum of its proper divisors (1).

81213057307 is an equidigital number, since it uses as much as digits as its factorization.

81213057307 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 35280, while the sum is 37.

The spelling of 81213057307 in words is "eighty-one billion, two hundred thirteen million, fifty-seven thousand, three hundred seven".