216658890 has 144 divisors (see below), whose sum is σ = 665246088. Its totient is φ = 48771072.

The previous prime is 216658889. The next prime is 216658903. The reversal of 216658890 is 98856612.

216658890 is a `hidden beast` number, since 2 + 1 + 66 + 588 + 9 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 163558521 + 53100369 = 12789^2 + 7287^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 321594 + ... + 322266.

Almost surely, 2^216658890 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216658890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (332623044).

216658890 is an abundant number, since it is smaller than the sum of its proper divisors (448587198).

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

216658890 is a wasteful number, since it uses less digits than its factorization.

216658890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 773 (or 763 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The square root of 216658890 is about 14719.3372812773. The cubic root of 216658890 is about 600.6094640463.

The spelling of 216658890 in words is "two hundred sixteen million, six hundred fifty-eight thousand, eight hundred ninety".