216901 has 2 divisors, whose sum is σ = 216902. Its totient is φ = 216900.

The previous prime is 216899. The next prime is 216911. The reversal of 216901 is 109612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 216225 + 676 = 465^2 + 26^2 .

It is a cyclic number.

It is not a de Polignac number, because 216901 - 2¹ = 216899 is a prime.

Together with 216899, it forms a pair of twin primes.

It is an Ulam number.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108450 + 108451.

It is an arithmetic number, because the mean of its divisors is an integer number (108451).

2²¹⁶⁹⁰¹ is an apocalyptic number.

It is an amenable number.

216901 is a deficient number, since it is larger than the sum of its proper divisors (1).

216901 is an equidigital number, since it uses as much as digits as its factorization.

216901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108, while the sum is 19.

The square root of 216901 is about 465.7263144809. The cubic root of 216901 is about 60.0833101959.

The spelling of 216901 in words is "two hundred sixteen thousand, nine hundred one".