206564778 has 48 divisors (see below), whose sum is σ = 513564480. Its totient is φ = 58779648.

The previous prime is 206564777. The next prime is 206564783. The reversal of 206564778 is 877465602.

It is not an unprimeable number, because it can be changed into a prime (206564777) 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 23 ways as a sum of consecutive naturals, for example, 29193 + ... + 35571.

It is an arithmetic number, because the mean of its divisors is an integer number (10699260).

Almost surely, 2^206564778 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 206564778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (256782240).

206564778 is an abundant number, since it is smaller than the sum of its proper divisors (306999702).

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

206564778 is a wasteful number, since it uses less digits than its factorization.

206564778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6651 (or 6648 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 45.

The square root of 206564778 is about 14372.3616013514. The cubic root of 206564778 is about 591.1332981127.

The spelling of 206564778 in words is "two hundred six million, five hundred sixty-four thousand, seven hundred seventy-eight".