81070657 has 2 divisors, whose sum is σ = 81070658. Its totient is φ = 81070656.

The previous prime is 81070601. The next prime is 81070679. The reversal of 81070657 is 75607018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77862976 + 3207681 = 8824^2 + 1791^2 .

It is a cyclic number.

It is not a de Polignac number, because 81070657 - 2¹¹ = 81068609 is a prime.

It is not a weakly prime, because it can be changed into another prime (81070697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40535328 + 40535329.

It is an arithmetic number, because the mean of its divisors is an integer number (40535329).

Almost surely, 2^81070657 is an apocalyptic number.

It is an amenable number.

81070657 is a deficient number, since it is larger than the sum of its proper divisors (1).

81070657 is an equidigital number, since it uses as much as digits as its factorization.

81070657 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11760, while the sum is 34.

The square root of 81070657 is about 9003.9245332244. The cubic root of 81070657 is about 432.8006432050.

The spelling of 81070657 in words is "eighty-one million, seventy thousand, six hundred fifty-seven".