161645965 has 12 divisors (see below), whose sum is σ = 210045204. Its totient is φ = 119368704.

The previous prime is 161645963. The next prime is 161645969. The reversal of 161645965 is 569546161.

It can be written as a sum of positive squares in 6 ways, for example, as 41809156 + 119836809 = 6466^2 + 10947^2 .

It is not a de Polignac number, because 161645965 - 2¹ = 161645963 is a prime.

It is a super-2 number, since 2×161645965² = 52258836001562450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161645963) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 94804 + ... + 96493.

It is an arithmetic number, because the mean of its divisors is an integer number (17503767).

Almost surely, 2^161645965 is an apocalyptic number.

It is an amenable number.

161645965 is a deficient number, since it is larger than the sum of its proper divisors (48399239).

161645965 is a wasteful number, since it uses less digits than its factorization.

161645965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191328 (or 191315 counting only the distinct ones).

The product of its digits is 194400, while the sum is 43.

The square root of 161645965 is about 12714.0066462150. The cubic root of 161645965 is about 544.7387744549.

The spelling of 161645965 in words is "one hundred sixty-one million, six hundred forty-five thousand, nine hundred sixty-five".