161899849 has 2 divisors, whose sum is σ = 161899850. Its totient is φ = 161899848.

The previous prime is 161899841. The next prime is 161899861. The reversal of 161899849 is 948998161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 99600400 + 62299449 = 9980^2 + 7893^2 .

It is an emirp because it is prime and its reverse (948998161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161899849 - 2³ = 161899841 is a prime.

It is a super-3 number, since 3×161899849³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 161899849.

It is not a weakly prime, because it can be changed into another prime (161899841) 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, 80949924 + 80949925.

It is an arithmetic number, because the mean of its divisors is an integer number (80949925).

Almost surely, 2^161899849 is an apocalyptic number.

It is an amenable number.

161899849 is a deficient number, since it is larger than the sum of its proper divisors (1).

161899849 is an equidigital number, since it uses as much as digits as its factorization.

161899849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1119744, while the sum is 55.

The square root of 161899849 is about 12723.9871502607. The cubic root of 161899849 is about 545.0238173807.

The spelling of 161899849 in words is "one hundred sixty-one million, eight hundred ninety-nine thousand, eight hundred forty-nine".