165563801 has 4 divisors (see below), whose sum is σ = 178299492. Its totient is φ = 152828112.

The previous prime is 165563779. The next prime is 165563809. The reversal of 165563801 is 108365561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 108365561 = 617 ⋅175633.

It can be written as a sum of positive squares in 2 ways, for example, as 108576400 + 56987401 = 10420^2 + 7549^2 .

It is a cyclic number.

It is not a de Polignac number, because 165563801 - 2¹⁰ = 165562777 is a prime.

It is a super-2 number, since 2×165563801² = 54822744403135202, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165563809) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6367826 + ... + 6367851.

It is an arithmetic number, because the mean of its divisors is an integer number (44574873).

Almost surely, 2^165563801 is an apocalyptic number.

It is an amenable number.

165563801 is a deficient number, since it is larger than the sum of its proper divisors (12735691).

165563801 is a wasteful number, since it uses less digits than its factorization.

165563801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12735690.

The product of its (nonzero) digits is 21600, while the sum is 35.

The square root of 165563801 is about 12867.1597876144. The cubic root of 165563801 is about 549.1046600797.

It can be divided in two parts, 1655 and 63801, that added together give a palindrome (65456).

The spelling of 165563801 in words is "one hundred sixty-five million, five hundred sixty-three thousand, eight hundred one".