81282557791 has 2 divisors, whose sum is σ = 81282557792. Its totient is φ = 81282557790.

The previous prime is 81282557777. The next prime is 81282557831. The reversal of 81282557791 is 19775528218.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81282557791 - 2⁷ = 81282557663 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81282557731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40641278895 + 40641278896.

It is an arithmetic number, because the mean of its divisors is an integer number (40641278896).

Almost surely, 2^81282557791 is an apocalyptic number.

81282557791 is a deficient number, since it is larger than the sum of its proper divisors (1).

81282557791 is an equidigital number, since it uses as much as digits as its factorization.

81282557791 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2822400, while the sum is 55.

The spelling of 81282557791 in words is "eighty-one billion, two hundred eighty-two million, five hundred fifty-seven thousand, seven hundred ninety-one".