161211121 has 2 divisors, whose sum is σ = 161211122. Its totient is φ = 161211120.

The previous prime is 161211103. The next prime is 161211131. The reversal of 161211121 is 121112161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 128595600 + 32615521 = 11340^2 + 5711^2 .

It is a cyclic number.

It is not a de Polignac number, because 161211121 - 2¹¹ = 161209073 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 161211095 and 161211104.

It is not a weakly prime, because it can be changed into another prime (161211101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80605560 + 80605561.

It is an arithmetic number, because the mean of its divisors is an integer number (80605561).

Almost surely, 2^161211121 is an apocalyptic number.

It is an amenable number.

161211121 is a deficient number, since it is larger than the sum of its proper divisors (1).

161211121 is an equidigital number, since it uses as much as digits as its factorization.

161211121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24, while the sum is 16.

The square root of 161211121 is about 12696.8941477828. The cubic root of 161211121 is about 544.2498683182.

Adding to 161211121 its reverse (121112161), we get a palindrome (282323282).

The spelling of 161211121 in words is "one hundred sixty-one million, two hundred eleven thousand, one hundred twenty-one".