181698440121 has 27 divisors (see below), whose sum is σ = 288504064303. Its totient is φ = 110111741520.

The previous prime is 181698440113. The next prime is 181698440177. The reversal of 181698440121 is 121044896181.

The square root of 181698440121 is 426261.

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

181698440121 is a `hidden beast` number, since 1 + 8 + 169 + 84 + 401 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 99423549225 + 82274890896 = 315315^2 + 286836^2 .

It is not a de Polignac number, because 181698440121 - 2³ = 181698440113 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (181698440321) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 14060155 + ... + 14073071.

Almost surely, 2^181698440121 is an apocalyptic number.

181698440121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

181698440121 is the 426261-st square number.

181698440121 is the 213131-st centered octagonal number.

It is an amenable number.

181698440121 is a deficient number, since it is larger than the sum of its proper divisors (106805624182).

181698440121 is an frugal number, since it uses more digits than its factorization.

181698440121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25862 (or 12931 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 45.

The spelling of 181698440121 in words is "one hundred eighty-one billion, six hundred ninety-eight million, four hundred forty thousand, one hundred twenty-one".