161573865 has 16 divisors (see below), whose sum is σ = 273725568. Its totient is φ = 81103616.

The previous prime is 161573849. The next prime is 161573879. The reversal of 161573865 is 568375161.

It is a cyclic number.

It is not a de Polignac number, because 161573865 - 2⁴ = 161573849 is a prime.

It is a super-2 number, since 2×161573865² = 52212227702076450, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 316557 + ... + 317066.

It is an arithmetic number, because the mean of its divisors is an integer number (17107848).

Almost surely, 2^161573865 is an apocalyptic number.

161573865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161573865 is a deficient number, since it is larger than the sum of its proper divisors (112151703).

161573865 is a wasteful number, since it uses less digits than its factorization.

161573865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 633648.

The product of its digits is 151200, while the sum is 42.

The square root of 161573865 is about 12711.1708744710. The cubic root of 161573865 is about 544.6577712853.

The spelling of 161573865 in words is "one hundred sixty-one million, five hundred seventy-three thousand, eight hundred sixty-five".