165564211 has 4 divisors (see below), whose sum is σ = 170905024. Its totient is φ = 160223400.

The previous prime is 165564197. The next prime is 165564251. The reversal of 165564211 is 112465561.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 165564211 - 2¹⁹ = 165039923 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 5340781 = 165564211 / (1 + 6 + 5 + 5 + 6 + 4 + 2 + 1 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165564251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2670360 + ... + 2670421.

It is an arithmetic number, because the mean of its divisors is an integer number (42726256).

Almost surely, 2^165564211 is an apocalyptic number.

165564211 is a deficient number, since it is larger than the sum of its proper divisors (5340813).

165564211 is an equidigital number, since it uses as much as digits as its factorization.

165564211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5340812.

The product of its digits is 7200, while the sum is 31.

The square root of 165564211 is about 12867.1757196364. The cubic root of 165564211 is about 549.1051133445.

The spelling of 165564211 in words is "one hundred sixty-five million, five hundred sixty-four thousand, two hundred eleven".