161209969 has 2 divisors, whose sum is σ = 161209970. Its totient is φ = 161209968.

The previous prime is 161209957. The next prime is 161210011. The reversal of 161209969 is 969902161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 160959969 + 250000 = 12687^2 + 500^2 .

It is an emirp because it is prime and its reverse (969902161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161209969 - 2²⁵ = 127655537 is a prime.

It is a super-2 number, since 2×161209969² = 51977308209961922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (161209669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80604984 + 80604985.

It is an arithmetic number, because the mean of its divisors is an integer number (80604985).

Almost surely, 2^161209969 is an apocalyptic number.

It is an amenable number.

161209969 is a deficient number, since it is larger than the sum of its proper divisors (1).

161209969 is an equidigital number, since it uses as much as digits as its factorization.

161209969 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 52488, while the sum is 43.

The square root of 161209969 is about 12696.8487822766. The cubic root of 161209969 is about 544.2485719284.

The spelling of 161209969 in words is "one hundred sixty-one million, two hundred nine thousand, nine hundred sixty-nine".