160691561 has 2 divisors, whose sum is σ = 160691562. Its totient is φ = 160691560.

The previous prime is 160691549. The next prime is 160691579. The reversal of 160691561 is 165196061.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 117592336 + 43099225 = 10844^2 + 6565^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-160691561 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (160691591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80345780 + 80345781.

It is an arithmetic number, because the mean of its divisors is an integer number (80345781).

Almost surely, 2^160691561 is an apocalyptic number.

It is an amenable number.

160691561 is a deficient number, since it is larger than the sum of its proper divisors (1).

160691561 is an equidigital number, since it uses as much as digits as its factorization.

160691561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9720, while the sum is 35.

The square root of 160691561 is about 12676.4175144242. The cubic root of 160691561 is about 543.6645596849.

The spelling of 160691561 in words is "one hundred sixty million, six hundred ninety-one thousand, five hundred sixty-one".