161233561 has 2 divisors, whose sum is σ = 161233562. Its totient is φ = 161233560.

The previous prime is 161233543. The next prime is 161233571. The reversal of 161233561 is 165332161.

161233561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 89661961 + 71571600 = 9469^2 + 8460^2 .

It is a cyclic number.

It is not a de Polignac number, because 161233561 - 2⁵ = 161233529 is a prime.

It is a super-2 number, since 2×161233561² = 51992522385481442, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (161233571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80616780 + 80616781.

It is an arithmetic number, because the mean of its divisors is an integer number (80616781).

Almost surely, 2^161233561 is an apocalyptic number.

It is an amenable number.

161233561 is a deficient number, since it is larger than the sum of its proper divisors (1).

161233561 is an equidigital number, since it uses as much as digits as its factorization.

161233561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3240, while the sum is 28.

The square root of 161233561 is about 12697.7777977093. Note that the first 4 decimals coincide. The cubic root of 161233561 is about 544.2751196787.

The spelling of 161233561 in words is "one hundred sixty-one million, two hundred thirty-three thousand, five hundred sixty-one".