161394224121 has 27 divisors (see below), whose sum is σ = 252461628237. Its totient is φ = 99309880800.

The previous prime is 161394224099. The next prime is 161394224129. The reversal of 161394224121 is 121422493161.

The square root of 161394224121 is 401739.

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

161394224121 is a `hidden beast` number, since 1 + 6 + 1 + 394 + 2 + 241 + 21 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 6208652025 + 155185572096 = 78795^2 + 393936^2 .

It is not a de Polignac number, because 161394224121 - 2²⁵ = 161360669689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161394224129) 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, 15662671 + ... + 15672971.

Almost surely, 2^161394224121 is an apocalyptic number.

161394224121 is the 401739-th square number.

161394224121 is the 200870-th centered octagonal number.

It is an amenable number.

161394224121 is a deficient number, since it is larger than the sum of its proper divisors (91067404116).

161394224121 is an frugal number, since it uses more digits than its factorization.

161394224121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20634 (or 10317 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

Multiplying 161394224121 by its sum of digits (36), we get a square (5810192068356 = 2410434²).

The spelling of 161394224121 in words is "one hundred sixty-one billion, three hundred ninety-four million, two hundred twenty-four thousand, one hundred twenty-one".