161561093 has 2 divisors, whose sum is σ = 161561094. Its totient is φ = 161561092.

The previous prime is 161561089. The next prime is 161561111. The reversal of 161561093 is 390165161.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 140612164 + 20948929 = 11858^2 + 4577^2 .

It is a cyclic number.

It is not a de Polignac number, because 161561093 - 2² = 161561089 is a prime.

It is a super-2 number, since 2×161561093² = 52203973542709298, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161561993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80780546 + 80780547.

It is an arithmetic number, because the mean of its divisors is an integer number (80780547).

Almost surely, 2^161561093 is an apocalyptic number.

It is an amenable number.

161561093 is a deficient number, since it is larger than the sum of its proper divisors (1).

161561093 is an equidigital number, since it uses as much as digits as its factorization.

161561093 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4860, while the sum is 32.

The square root of 161561093 is about 12710.6684717996. The cubic root of 161561093 is about 544.6434196401.

The spelling of 161561093 in words is "one hundred sixty-one million, five hundred sixty-one thousand, ninety-three".