161990218 has 24 divisors (see below), whose sum is σ = 270246348. Its totient is φ = 72738432.

The previous prime is 161990119. The next prime is 161990237. The reversal of 161990218 is 812099161.

161990218 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 6 ways, for example, as 22915369 + 139074849 = 4787^2 + 11793^2 .

It is a Harshad number since it is a multiple of its sum of digits (37).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6030 + ... + 18982.

Almost surely, 2^161990218 is an apocalyptic number.

161990218 is a deficient number, since it is larger than the sum of its proper divisors (108256130).

161990218 is a wasteful number, since it uses less digits than its factorization.

161990218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13018 (or 13005 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 37.

The square root of 161990218 is about 12727.5377823049. The cubic root of 161990218 is about 545.1252053611.

The spelling of 161990218 in words is "one hundred sixty-one million, nine hundred ninety thousand, two hundred eighteen".