161211909 has 8 divisors (see below), whose sum is σ = 215168800. Its totient is φ = 107364816.

The previous prime is 161211907. The next prime is 161211931. The reversal of 161211909 is 909112161.

161211909 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 161211909 - 2¹ = 161211907 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161211907) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23959 + ... + 29940.

It is an arithmetic number, because the mean of its divisors is an integer number (26896100).

Almost surely, 2^161211909 is an apocalyptic number.

It is an amenable number.

161211909 is a deficient number, since it is larger than the sum of its proper divisors (53956891).

161211909 is an equidigital number, since it uses as much as digits as its factorization.

161211909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54899.

The product of its (nonzero) digits is 972, while the sum is 30.

The square root of 161211909 is about 12696.9251789557. The cubic root of 161211909 is about 544.2507550812.

The spelling of 161211909 in words is "one hundred sixty-one million, two hundred eleven thousand, nine hundred nine".