81257615285291 has 2 divisors, whose sum is σ = 81257615285292. Its totient is φ = 81257615285290.

The previous prime is 81257615285267. The next prime is 81257615285303. The reversal of 81257615285291 is 19258251675218.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81257615285291 - 2¹⁰ = 81257615284267 is a prime.

It is not a weakly prime, because it can be changed into another prime (81257615285491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40628807642645 + 40628807642646.

It is an arithmetic number, because the mean of its divisors is an integer number (40628807642646).

Almost surely, 2^{81257615285291} is an apocalyptic number.

81257615285291 is a deficient number, since it is larger than the sum of its proper divisors (1).

81257615285291 is an equidigital number, since it uses as much as digits as its factorization.

81257615285291 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24192000, while the sum is 62.

The spelling of 81257615285291 in words is "eighty-one trillion, two hundred fifty-seven billion, six hundred fifteen million, two hundred eighty-five thousand, two hundred ninety-one".