161243221 has 2 divisors, whose sum is σ = 161243222. Its totient is φ = 161243220.

The previous prime is 161243213. The next prime is 161243231. The reversal of 161243221 is 122342161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 126315121 + 34928100 = 11239^2 + 5910^2 .

It is an emirp because it is prime and its reverse (122342161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161243221 - 2³ = 161243213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 161243192 and 161243201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161243231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80621610 + 80621611.

It is an arithmetic number, because the mean of its divisors is an integer number (80621611).

Almost surely, 2^161243221 is an apocalyptic number.

It is an amenable number.

161243221 is a deficient number, since it is larger than the sum of its proper divisors (1).

161243221 is an equidigital number, since it uses as much as digits as its factorization.

161243221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576, while the sum is 22.

The square root of 161243221 is about 12698.1581735305. The cubic root of 161243221 is about 544.2859891954.

Adding to 161243221 its reverse (122342161), we get a palindrome (283585382).

The spelling of 161243221 in words is "one hundred sixty-one million, two hundred forty-three thousand, two hundred twenty-one".