216690864 has 160 divisors (see below), whose sum is σ = 628959744. Its totient is φ = 63866880.

The previous prime is 216690841. The next prime is 216690869. The reversal of 216690864 is 468096612.

It is not an unprimeable number, because it can be changed into a prime (216690869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2968332 + ... + 2968404.

Almost surely, 2^216690864 is an apocalyptic number.

216690864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216690864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (314479872).

216690864 is an abundant number, since it is smaller than the sum of its proper divisors (412268880).

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

216690864 is a wasteful number, since it uses less digits than its factorization.

216690864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235 (or 229 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 42.

The square root of 216690864 is about 14720.4233634770. The cubic root of 216690864 is about 600.6390080950.

The spelling of 216690864 in words is "two hundred sixteen million, six hundred ninety thousand, eight hundred sixty-four".