161981155 has 8 divisors (see below), whose sum is σ = 222145632. Its totient is φ = 111072768.

The previous prime is 161981147. The next prime is 161981167. The reversal of 161981155 is 551189161.

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

It is a cyclic number.

It is not a de Polignac number, because 161981155 - 2³ = 161981147 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2313982 + ... + 2314051.

It is an arithmetic number, because the mean of its divisors is an integer number (27768204).

Almost surely, 2^161981155 is an apocalyptic number.

161981155 is a deficient number, since it is larger than the sum of its proper divisors (60164477).

161981155 is an equidigital number, since it uses as much as digits as its factorization.

161981155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4628045.

The product of its digits is 10800, while the sum is 37.

The square root of 161981155 is about 12727.1817383111. The cubic root of 161981155 is about 545.1150389821.

The spelling of 161981155 in words is "one hundred sixty-one million, nine hundred eighty-one thousand, one hundred fifty-five".