206139784 has 16 divisors (see below), whose sum is σ = 386668620. Its totient is φ = 103028160.

The previous prime is 206139763. The next prime is 206139793. The reversal of 206139784 is 487931602.

It can be written as a sum of positive squares in 2 ways, for example, as 205119684 + 1020100 = 14322^2 + 1010^2 .

It is a super-2 number, since 2×206139784² = 84987221095133312, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28894 + ... + 35314.

Almost surely, 2^206139784 is an apocalyptic number.

It is an amenable number.

206139784 is a deficient number, since it is larger than the sum of its proper divisors (180528836).

206139784 is a wasteful number, since it uses less digits than its factorization.

206139784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10440 (or 10436 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 40.

The square root of 206139784 is about 14357.5688749872. The cubic root of 206139784 is about 590.7276132716.

The spelling of 206139784 in words is "two hundred six million, one hundred thirty-nine thousand, seven hundred eighty-four".