219640806 has 96 divisors (see below), whose sum is σ = 609493248. Its totient is φ = 55494720.

The previous prime is 219640801. The next prime is 219640819. The reversal of 219640806 is 608046912.

219640806 is a `hidden beast` number, since 2 + 1 + 9 + 640 + 8 + 0 + 6 = 666.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (219640801) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 49141 + ... + 53423.

It is an arithmetic number, because the mean of its divisors is an integer number (6348888).

Almost surely, 2^219640806 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 219640806, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (304746624).

219640806 is an abundant number, since it is smaller than the sum of its proper divisors (389852442).

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

219640806 is a wasteful number, since it uses less digits than its factorization.

219640806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4346 (or 4343 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 219640806 is about 14820.2836005253. The cubic root of 219640806 is about 603.3523513502.

The spelling of 219640806 in words is "two hundred nineteen million, six hundred forty thousand, eight hundred six".