161974155 has 24 divisors (see below), whose sum is σ = 301471632. Its totient is φ = 74044992.

The previous prime is 161974151. The next prime is 161974159. The reversal of 161974155 is 551479161.

It is an interprime number because it is at equal distance from previous prime (161974151) and next prime (161974159).

It is not a de Polignac number, because 161974155 - 2² = 161974151 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (161974151) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 109452 + ... + 110921.

It is an arithmetic number, because the mean of its divisors is an integer number (12561318).

Almost surely, 2^161974155 is an apocalyptic number.

161974155 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

161974155 is a deficient number, since it is larger than the sum of its proper divisors (139497477).

161974155 is a wasteful number, since it uses less digits than its factorization.

161974155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220395 (or 220388 counting only the distinct ones).

The product of its digits is 37800, while the sum is 39.

The square root of 161974155 is about 12726.9067333740. The cubic root of 161974155 is about 545.1071865043.

The spelling of 161974155 in words is "one hundred sixty-one million, nine hundred seventy-four thousand, one hundred fifty-five".