161217945 has 160 divisors (see below), whose sum is σ = 361025280. Its totient is φ = 67184640.

The previous prime is 161217929. The next prime is 161218007. The reversal of 161217945 is 549712161.

161217945 = T₄₁₁₀ + T₄₁₁₁ + ... + T₄₁₂₈.

161217945 is nontrivially palindromic in base 2.

It is not a de Polignac number, because 161217945 - 2⁴ = 161217929 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 2208429 + ... + 2208501.

It is an arithmetic number, because the mean of its divisors is an integer number (2256408).

Almost surely, 2^161217945 is an apocalyptic number.

161217945 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161217945 is an abundant number, since it is smaller than the sum of its proper divisors (199807335).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161217945 is a wasteful number, since it uses less digits than its factorization.

161217945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157 (or 148 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 161217945 is about 12697.1628720750. The cubic root of 161217945 is about 544.2575475003.

The spelling of 161217945 in words is "one hundred sixty-one million, two hundred seventeen thousand, nine hundred forty-five".