161833221225 has 81 divisors (see below), whose sum is σ = 314025675717. Its totient is φ = 79633120320.

The previous prime is 161833221223. The next prime is 161833221241. The reversal of 161833221225 is 522122338161.

The square root of 161833221225 is 402285.

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

161833221225 is a `hidden beast` number, since 1 + 618 + 3 + 3 + 2 + 2 + 12 + 25 = 666.

161833221225 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 41712752169 + 120120469056 = 204237^2 + 346584^2 .

It is not a de Polignac number, because 161833221225 - 2¹ = 161833221223 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 161833221225.

It is not an unprimeable number, because it can be changed into a prime (161833221223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 78444544 + ... + 78446606.

Almost surely, 2^161833221225 is an apocalyptic number.

161833221225 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

161833221225 is the 402285-th square number.

161833221225 is the 201143-rd centered octagonal number.

It is an amenable number.

161833221225 is a deficient number, since it is larger than the sum of its proper divisors (152192454492).

161833221225 is an equidigital number, since it uses as much as digits as its factorization.

161833221225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4168 (or 2084 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

Multiplying 161833221225 by its sum of digits (36), we get a square (5825995964100 = 2413710²).

Adding to 161833221225 its reverse (522122338161), we get a palindrome (683955559386).

The spelling of 161833221225 in words is "one hundred sixty-one billion, eight hundred thirty-three million, two hundred twenty-one thousand, two hundred twenty-five".