216997989 has 8 divisors (see below), whose sum is σ = 311586912. Its totient is φ = 133537200.

The previous prime is 216997987. The next prime is 216997997. The reversal of 216997989 is 989799612.

It is a happy number.

216997989 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 216997989 - 2¹ = 216997987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216997987) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2781987 + ... + 2782064.

It is an arithmetic number, because the mean of its divisors is an integer number (38948364).

Almost surely, 2^216997989 is an apocalyptic number.

It is an amenable number.

216997989 is a deficient number, since it is larger than the sum of its proper divisors (94588923).

216997989 is a wasteful number, since it uses less digits than its factorization.

216997989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5564067.

The product of its digits is 4408992, while the sum is 60.

The square root of 216997989 is about 14730.8516047104. The cubic root of 216997989 is about 600.9226443739.

The spelling of 216997989 in words is "two hundred sixteen million, nine hundred ninety-seven thousand, nine hundred eighty-nine".