161905215 has 16 divisors (see below), whose sum is σ = 259790688. Its totient is φ = 86102016.

The previous prime is 161905201. The next prime is 161905223. The reversal of 161905215 is 512509161.

It is not a de Polignac number, because 161905215 - 2⁴ = 161905199 is a prime.

It is a congruent number.

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 9994 + ... + 20583.

It is an arithmetic number, because the mean of its divisors is an integer number (16236918).

Almost surely, 2^161905215 is an apocalyptic number.

161905215 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

161905215 is a deficient number, since it is larger than the sum of its proper divisors (97885473).

161905215 is a wasteful number, since it uses less digits than its factorization.

161905215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30938.

The product of its (nonzero) digits is 2700, while the sum is 30.

The square root of 161905215 is about 12724.1980100909. The cubic root of 161905215 is about 545.0298387277.

The spelling of 161905215 in words is "one hundred sixty-one million, nine hundred five thousand, two hundred fifteen".