81255857 has 2 divisors, whose sum is σ = 81255858. Its totient is φ = 81255856.

The previous prime is 81255829. The next prime is 81255877. The reversal of 81255857 is 75855218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67387681 + 13868176 = 8209^2 + 3724^2 .

It is a cyclic number.

It is not a de Polignac number, because 81255857 - 2²⁴ = 64478641 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81255817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40627928 + 40627929.

It is an arithmetic number, because the mean of its divisors is an integer number (40627929).

Almost surely, 2^81255857 is an apocalyptic number.

It is an amenable number.

81255857 is a deficient number, since it is larger than the sum of its proper divisors (1).

81255857 is an equidigital number, since it uses as much as digits as its factorization.

81255857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 112000, while the sum is 41.

The square root of 81255857 is about 9014.2030707101. The cubic root of 81255857 is about 433.1299597280.

The spelling of 81255857 in words is "eighty-one million, two hundred fifty-five thousand, eight hundred fifty-seven".