17987906161 has 9 divisors (see below), whose sum is σ = 18254488843. Its totient is φ = 17725167040.

The previous prime is 17987906149. The next prime is 17987906177. The reversal of 17987906161 is 16160978971.

The square root of 17987906161 is 134119.

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., 8664072561 + 9323833600 = 93081^2 + 96560^2 .

It is a de Polignac number, because none of the positive numbers 2^k-17987906161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (17987996161) 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, 9521505 + ... + 9523393.

Almost surely, 2^17987906161 is an apocalyptic number.

17987906161 is the 134119-th square number.

17987906161 is the 67060-th centered octagonal number.

It is an amenable number.

17987906161 is a deficient number, since it is larger than the sum of its proper divisors (266582682).

17987906161 is an frugal number, since it uses more digits than its factorization.

17987906161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3920 (or 1960 counting only the distinct ones).

The product of its (nonzero) digits is 1143072, while the sum is 55.

The spelling of 17987906161 in words is "seventeen billion, nine hundred eighty-seven million, nine hundred six thousand, one hundred sixty-one".