206156778568 has 16 divisors (see below), whose sum is σ = 416278110780. Its totient is φ = 95149282368.

The previous prime is 206156778563. The next prime is 206156778571. The reversal of 206156778568 is 865877651602.

It can be written as a sum of positive squares in 2 ways, for example, as 206117816004 + 38962564 = 454002^2 + 6242^2 .

It is not an unprimeable number, because it can be changed into a prime (206156778563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 991138255 + ... + 991138462.

Almost surely, 2^206156778568 is an apocalyptic number.

It is an amenable number.

206156778568 is an abundant number, since it is smaller than the sum of its proper divisors (210121332212).

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

206156778568 is a wasteful number, since it uses less digits than its factorization.

206156778568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1982276736 (or 1982276732 counting only the distinct ones).

The product of its (nonzero) digits is 33868800, while the sum is 61.

The spelling of 206156778568 in words is "two hundred six billion, one hundred fifty-six million, seven hundred seventy-eight thousand, five hundred sixty-eight".