161645441 has 2 divisors, whose sum is σ = 161645442. Its totient is φ = 161645440.

The previous prime is 161645437. The next prime is 161645443. The reversal of 161645441 is 144546161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 160782400 + 863041 = 12680^2 + 929^2 .

It is a cyclic number.

It is not a de Polignac number, because 161645441 - 2² = 161645437 is a prime.

It is a super-2 number, since 2×161645441² = 52258497192168962, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 161645443, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is equal to p_9061565 and since 161645441 and 9061565 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 161645398 and 161645407.

It is not a weakly prime, because it can be changed into another prime (161645443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80822720 + 80822721.

It is an arithmetic number, because the mean of its divisors is an integer number (80822721).

Almost surely, 2^161645441 is an apocalyptic number.

It is an amenable number.

161645441 is a deficient number, since it is larger than the sum of its proper divisors (1).

161645441 is an equidigital number, since it uses as much as digits as its factorization.

161645441 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11520, while the sum is 32.

The square root of 161645441 is about 12713.9860390044. The cubic root of 161645441 is about 544.7381858364.

The spelling of 161645441 in words is "one hundred sixty-one million, six hundred forty-five thousand, four hundred forty-one".