206439840 has 240 divisors, whose sum is σ = 772240392. Its totient is φ = 51757056.

The previous prime is 206439833. The next prime is 206439847. The reversal of 206439840 is 48934602.

It is a happy number.

206439840 is a `hidden beast` number, since 2 + 0 + 643 + 9 + 8 + 4 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (206439833) and next prime (206439847).

It can be written as a sum of positive squares in 4 ways, for example, as 141991056 + 64448784 = 11916^2 + 8028^2 .

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 206439795 and 206439804.

It is not an unprimeable number, because it can be changed into a prime (206439847) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 219852 + ... + 220788.

Almost surely, 2^206439840 is an apocalyptic number.

206439840 is a gapful number since it is divisible by the number (20) 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 206439840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (386120196).

206439840 is an abundant number, since it is smaller than the sum of its proper divisors (565800552).

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

206439840 is a wasteful number, since it uses less digits than its factorization.

206439840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 981 (or 964 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 206439840 is about 14368.0144766074. The cubic root of 206439840 is about 591.0140943326.

The spelling of 206439840 in words is "two hundred six million, four hundred thirty-nine thousand, eight hundred forty".