161232121 has 2 divisors, whose sum is σ = 161232122. Its totient is φ = 161232120.

The previous prime is 161232101. The next prime is 161232163. The reversal of 161232121 is 121232161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 138297600 + 22934521 = 11760^2 + 4789^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161232121 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is not a weakly prime, because it can be changed into another prime (161232101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80616060 + 80616061.

It is an arithmetic number, because the mean of its divisors is an integer number (80616061).

Almost surely, 2^161232121 is an apocalyptic number.

It is an amenable number.

161232121 is a deficient number, since it is larger than the sum of its proper divisors (1).

161232121 is an equidigital number, since it uses as much as digits as its factorization.

161232121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 144, while the sum is 19.

The square root of 161232121 is about 12697.7210947477. The cubic root of 161232121 is about 544.2734993409.

Adding to 161232121 its reverse (121232161), we get a palindrome (282464282).

It can be divided in two parts, 1612 and 32121, that added together give a palindrome (33733).

The spelling of 161232121 in words is "one hundred sixty-one million, two hundred thirty-two thousand, one hundred twenty-one".