81070057 has 2 divisors, whose sum is σ = 81070058. Its totient is φ = 81070056.

The previous prime is 81070027. The next prime is 81070063. The reversal of 81070057 is 75007018.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78570496 + 2499561 = 8864^2 + 1581^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81070057 is a prime.

It is not a weakly prime, because it can be changed into another prime (81070027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40535028 + 40535029.

It is an arithmetic number, because the mean of its divisors is an integer number (40535029).

Almost surely, 2^81070057 is an apocalyptic number.

It is an amenable number.

81070057 is a deficient number, since it is larger than the sum of its proper divisors (1).

81070057 is an equidigital number, since it uses as much as digits as its factorization.

81070057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1960, while the sum is 28.

The square root of 81070057 is about 9003.8912143584. The cubic root of 81070057 is about 432.7995754902.

The spelling of 81070057 in words is "eighty-one million, seventy thousand, fifty-seven".