216805290 has 64 divisors (see below), whose sum is σ = 561883392. Its totient is φ = 53222400.

The previous prime is 216805261. The next prime is 216805307. The reversal of 216805290 is 92508612.

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, 245650 + ... + 246530.

It is an arithmetic number, because the mean of its divisors is an integer number (8779428).

Almost surely, 2^216805290 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216805290, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (280941696).

216805290 is an abundant number, since it is smaller than the sum of its proper divisors (345078102).

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

216805290 is a wasteful number, since it uses less digits than its factorization.

216805290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1535.

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 216805290 is about 14724.3094914498. The cubic root of 216805290 is about 600.7447141745.

The spelling of 216805290 in words is "two hundred sixteen million, eight hundred five thousand, two hundred ninety".