161911601 has 2 divisors, whose sum is σ = 161911602. Its totient is φ = 161911600.

The previous prime is 161911577. The next prime is 161911613. The reversal of 161911601 is 106119161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 152152225 + 9759376 = 12335^2 + 3124^2 .

It is a cyclic number.

It is not a de Polignac number, because 161911601 - 2⁶ = 161911537 is a prime.

It is not a weakly prime, because it can be changed into another prime (161913601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80955800 + 80955801.

It is an arithmetic number, because the mean of its divisors is an integer number (80955801).

Almost surely, 2^161911601 is an apocalyptic number.

It is an amenable number.

161911601 is a deficient number, since it is larger than the sum of its proper divisors (1).

161911601 is an equidigital number, since it uses as much as digits as its factorization.

161911601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 26.

The square root of 161911601 is about 12724.4489468110. The cubic root of 161911601 is about 545.0370044734.

The spelling of 161911601 in words is "one hundred sixty-one million, nine hundred eleven thousand, six hundred one".