161218188 has 30 divisors (see below), whose sum is σ = 421457036. Its totient is φ = 53739288.

The previous prime is 161218159. The next prime is 161218193. The reversal of 161218188 is 881812161.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 248470 + ... + 249117.

Almost surely, 2^161218188 is an apocalyptic number.

161218188 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

161218188 is an abundant number, since it is smaller than the sum of its proper divisors (260238848).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161218188 is a wasteful number, since it uses less digits than its factorization.

161218188 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 497603 (or 497592 counting only the distinct ones).

The product of its digits is 6144, while the sum is 36.

The square root of 161218188 is about 12697.1724411382. The cubic root of 161218188 is about 544.2578209491.

The spelling of 161218188 in words is "one hundred sixty-one million, two hundred eighteen thousand, one hundred eighty-eight".