8157911985 has 12 divisors (see below), whose sum is σ = 14140380852. Its totient is φ = 4350886368.

The previous prime is 8157911939. The next prime is 8157911989. The reversal of 8157911985 is 5891197518.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 6183620496 + 1974291489 = 78636^2 + 44433^2 .

It is not a de Polignac number, because 8157911985 - 2⁹ = 8157911473 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (8157911989) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 90643422 + ... + 90643511.

It is an arithmetic number, because the mean of its divisors is an integer number (1178365071).

Almost surely, 2^8157911985 is an apocalyptic number.

It is an amenable number.

8157911985 is a deficient number, since it is larger than the sum of its proper divisors (5982468867).

8157911985 is a wasteful number, since it uses less digits than its factorization.

8157911985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181286944 (or 181286941 counting only the distinct ones).

The product of its digits is 907200, while the sum is 54.

The square root of 8157911985 is about 90321.1602283762. The cubic root of 8157911985 is about 2013.0736852462.

The spelling of 8157911985 in words is "eight billion, one hundred fifty-seven million, nine hundred eleven thousand, nine hundred eighty-five".