163865601 has 27 divisors (see below), whose sum is σ = 252442723. Its totient is φ = 102408000.

The previous prime is 163865599. The next prime is 163865609. The reversal of 163865601 is 106568361.

It is a happy number.

The square root of 163865601 is 12801.

It is a perfect power (a square), and thus also a powerful number.

163865601 is a `hidden beast` number, since 16 + 3 + 86 + 560 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 127577025 + 36288576 = 11295^2 + 6024^2 .

It is not a de Polignac number, because 163865601 - 2¹ = 163865599 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (163865609) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 652726 + ... + 652976.

Almost surely, 2^163865601 is an apocalyptic number.

163865601 is the 12801-st square number.

163865601 is the 6401-st centered octagonal number.

It is an amenable number.

163865601 is a deficient number, since it is larger than the sum of its proper divisors (88577122).

163865601 is an equidigital number, since it uses as much as digits as its factorization.

163865601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 542 (or 271 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The cubic root of 163865601 is about 547.2208021646.

Multiplying 163865601 by its sum of digits (36), we get a square (5899161636 = 76806²).

The spelling of 163865601 in words is "one hundred sixty-three million, eight hundred sixty-five thousand, six hundred one".