71687857 has 2 divisors, whose sum is σ = 71687858. Its totient is φ = 71687856.

The previous prime is 71687843. The next prime is 71687873. The reversal of 71687857 is 75878617.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 63616576 + 8071281 = 7976^2 + 2841^2 .

It is a cyclic number.

It is not a de Polignac number, because 71687857 - 2⁷ = 71687729 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 71687857.

It is not a weakly prime, because it can be changed into another prime (71687887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35843928 + 35843929.

It is an arithmetic number, because the mean of its divisors is an integer number (35843929).

Almost surely, 2^71687857 is an apocalyptic number.

It is an amenable number.

71687857 is a deficient number, since it is larger than the sum of its proper divisors (1).

71687857 is an equidigital number, since it uses as much as digits as its factorization.

71687857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 658560, while the sum is 49.

The square root of 71687857 is about 8466.8681931397. The cubic root of 71687857 is about 415.4147052075.

The spelling of 71687857 in words is "seventy-one million, six hundred eighty-seven thousand, eight hundred fifty-seven".