81251351507 has 2 divisors, whose sum is σ = 81251351508. Its totient is φ = 81251351506.

The previous prime is 81251351497. The next prime is 81251351563. The reversal of 81251351507 is 70515315218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81251351507 - 2¹⁰ = 81251350483 is a prime.

It is not a weakly prime, because it can be changed into another prime (81251351407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40625675753 + 40625675754.

It is an arithmetic number, because the mean of its divisors is an integer number (40625675754).

Almost surely, 2^81251351507 is an apocalyptic number.

81251351507 is a deficient number, since it is larger than the sum of its proper divisors (1).

81251351507 is an equidigital number, since it uses as much as digits as its factorization.

81251351507 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 42000, while the sum is 38.

The spelling of 81251351507 in words is "eighty-one billion, two hundred fifty-one million, three hundred fifty-one thousand, five hundred seven".