161644121 has 2 divisors, whose sum is σ = 161644122. Its totient is φ = 161644120.

The previous prime is 161644097. The next prime is 161644123. The reversal of 161644121 is 121446161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 102738496 + 58905625 = 10136^2 + 7675^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161644121 is a prime.

It is a super-2 number, since 2×161644121² = 52257643707725282, which contains 22 as substring.

Together with 161644123, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (161644123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80822060 + 80822061.

It is an arithmetic number, because the mean of its divisors is an integer number (80822061).

Almost surely, 2^161644121 is an apocalyptic number.

It is an amenable number.

161644121 is a deficient number, since it is larger than the sum of its proper divisors (1).

161644121 is an equidigital number, since it uses as much as digits as its factorization.

161644121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1152, while the sum is 26.

The square root of 161644121 is about 12713.9341275626. The cubic root of 161644121 is about 544.7367030513.

The spelling of 161644121 in words is "one hundred sixty-one million, six hundred forty-four thousand, one hundred twenty-one".