8161687988 has 18 divisors (see below), whose sum is σ = 14312324838. Its totient is φ = 4072469440.

The previous prime is 8161687987. The next prime is 8161687999. The reversal of 8161687988 is 8897861618.

It can be written as a sum of positive squares in 3 ways, for example, as 1467502864 + 6694185124 = 38308^2 + 81818^2 .

It is a super-2 number, since 2×8161687988² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 8161687988.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8161687987) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1082006 + ... + 1089522.

Almost surely, 2^8161687988 is an apocalyptic number.

It is an amenable number.

8161687988 is a deficient number, since it is larger than the sum of its proper divisors (6150636850).

8161687988 is an equidigital number, since it uses as much as digits as its factorization.

8161687988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8563 (or 8040 counting only the distinct ones).

The product of its digits is 9289728, while the sum is 62.

The square root of 8161687988 is about 90342.0610125760. The cubic root of 8161687988 is about 2013.3842303869.

The spelling of 8161687988 in words is "eight billion, one hundred sixty-one million, six hundred eighty-seven thousand, nine hundred eighty-eight".