161242681 has 2 divisors, whose sum is σ = 161242682. Its totient is φ = 161242680.

The previous prime is 161242667. The next prime is 161242723. The reversal of 161242681 is 186242161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 104857600 + 56385081 = 10240^2 + 7509^2 .

It is a cyclic number.

It is not a de Polignac number, because 161242681 - 2⁵ = 161242649 is a prime.

It is a super-2 number, since 2×161242681² = 51998404352135522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (161242621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80621340 + 80621341.

It is an arithmetic number, because the mean of its divisors is an integer number (80621341).

Almost surely, 2^161242681 is an apocalyptic number.

It is an amenable number.

161242681 is a deficient number, since it is larger than the sum of its proper divisors (1).

161242681 is an equidigital number, since it uses as much as digits as its factorization.

161242681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4608, while the sum is 31.

The square root of 161242681 is about 12698.1369105865. The cubic root of 161242681 is about 544.2853815942.

The spelling of 161242681 in words is "one hundred sixty-one million, two hundred forty-two thousand, six hundred eighty-one".