216990 has 24 divisors (see below), whose sum is σ = 564408. Its totient is φ = 57840.

The previous prime is 216973. The next prime is 216991. The reversal of 216990 is 99612.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 216990.

It is not an unprimeable number, because it can be changed into a prime (216991) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1116 + ... + 1295.

It is an arithmetic number, because the mean of its divisors is an integer number (23517).

2²¹⁶⁹⁹⁰ is an apocalyptic number.

216990 is an abundant number, since it is smaller than the sum of its proper divisors (347418).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216990 is a wasteful number, since it uses less digits than its factorization.

216990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2424 (or 2421 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

The square root of 216990 is about 465.8218543607. The cubic root of 216990 is about 60.0915269759.

The spelling of 216990 in words is "two hundred sixteen thousand, nine hundred ninety".