216440989 has 4 divisors (see below), whose sum is σ = 227832640. Its totient is φ = 205049340.

The previous prime is 216440981. The next prime is 216440999. The reversal of 216440989 is 989044612.

216440989 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 216440989 - 2³ = 216440981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216440981) 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, 5695797 + ... + 5695834.

It is an arithmetic number, because the mean of its divisors is an integer number (56958160).

Almost surely, 2^216440989 is an apocalyptic number.

It is an amenable number.

216440989 is a deficient number, since it is larger than the sum of its proper divisors (11391651).

216440989 is a wasteful number, since it uses less digits than its factorization.

216440989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11391650.

The product of its (nonzero) digits is 124416, while the sum is 43.

The square root of 216440989 is about 14711.9335574900. The cubic root of 216440989 is about 600.4080455832.

The spelling of 216440989 in words is "two hundred sixteen million, four hundred forty thousand, nine hundred eighty-nine".