216664890 has 64 divisors (see below), whose sum is σ = 578092032. Its totient is φ = 51609600.

The previous prime is 216664879. The next prime is 216664909. The reversal of 216664890 is 98466612.

216664890 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3130 + ... + 21050.

It is an arithmetic number, because the mean of its divisors is an integer number (9032688).

Almost surely, 2^216664890 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216664890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (289046016).

216664890 is an abundant number, since it is smaller than the sum of its proper divisors (361427142).

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

216664890 is a wasteful number, since it uses less digits than its factorization.

216664890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17975.

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

The square root of 216664890 is about 14719.5410933901. The cubic root of 216664890 is about 600.6150082815.

The spelling of 216664890 in words is "two hundred sixteen million, six hundred sixty-four thousand, eight hundred ninety".