161718188164 has 27 divisors (see below), whose sum is σ = 306470996517. Its totient is φ = 74634338064.

The previous prime is 161718188161. The next prime is 161718188207. The reversal of 161718188164 is 461881817161.

The square root of 161718188164 is 402142.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 23922808900 + 137795379264 = 154670^2 + 371208^2 .

It is a Harshad number since it is a multiple of its sum of digits (52).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161718188161) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 10447959 + ... + 10463425.

Almost surely, 2^161718188164 is an apocalyptic number.

161718188164 is the 402142-nd square number.

It is an amenable number.

161718188164 is a deficient number, since it is larger than the sum of its proper divisors (144752808353).

161718188164 is an frugal number, since it uses more digits than its factorization.

161718188164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30964 (or 15482 counting only the distinct ones).

The product of its digits is 516096, while the sum is 52.

The spelling of 161718188164 in words is "one hundred sixty-one billion, seven hundred eighteen million, one hundred eighty-eight thousand, one hundred sixty-four".