216001 has 4 divisors (see below), whose sum is σ = 219604. Its totient is φ = 212400.

The previous prime is 215983. The next prime is 216023. The reversal of 216001 is 100612.

216001 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Cunningham number, because it is equal to 60³+1.

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

It can be written as a sum of positive squares in 2 ways, for example, as 39601 + 176400 = 199^2 + 420^2 .

It is a cyclic number.

It is not a de Polignac number, because 216001 - 2¹¹ = 213953 is a prime.

It is a deceptive number, since it divides R₂₁₆₀₀₀.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216061) 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, 1710 + ... + 1831.

It is an arithmetic number, because the mean of its divisors is an integer number (54901).

216001 is a Friedman number, since it can be written as 60^(2+1+0)+1, using all its digits and the basic arithmetic operations.

2²¹⁶⁰⁰¹ is an apocalyptic number.

It is an amenable number.

216001 is a deficient number, since it is larger than the sum of its proper divisors (3603).

216001 is an equidigital number, since it uses as much as digits as its factorization.

216001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3602.

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 216001 is about 464.7590773724. The cubic root of 216001 is about 60.0000925924. Note that the first 4 decimals are identical.

Adding to 216001 its reverse (100612), we get a palindrome (316613).

The spelling of 216001 in words is "two hundred sixteen thousand, one".