81255157 has 2 divisors, whose sum is σ = 81255158. Its totient is φ = 81255156.

The previous prime is 81255149. The next prime is 81255173. The reversal of 81255157 is 75155218.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64657681 + 16597476 = 8041^2 + 4074^2 .

It is a cyclic number.

It is not a de Polignac number, because 81255157 - 2³ = 81255149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81255127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40627578 + 40627579.

It is an arithmetic number, because the mean of its divisors is an integer number (40627579).

Almost surely, 2^81255157 is an apocalyptic number.

It is an amenable number.

81255157 is a deficient number, since it is larger than the sum of its proper divisors (1).

81255157 is an equidigital number, since it uses as much as digits as its factorization.

81255157 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14000, while the sum is 34.

The square root of 81255157 is about 9014.1642430122. The cubic root of 81255157 is about 433.1287159536.

The spelling of 81255157 in words is "eighty-one million, two hundred fifty-five thousand, one hundred fifty-seven".