206529921 has 24 divisors (see below), whose sum is σ = 325683176. Its totient is φ = 125349120.

The previous prime is 206529907. The next prime is 206529971. The reversal of 206529921 is 129925602.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 25250625 + 181279296 = 5025^2 + 13464^2 .

It is not a de Polignac number, because 206529921 - 2¹⁵ = 206497153 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (206529971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3550 + ... + 20631.

Almost surely, 2^206529921 is an apocalyptic number.

It is an amenable number.

206529921 is a deficient number, since it is larger than the sum of its proper divisors (119153255).

206529921 is a wasteful number, since it uses less digits than its factorization.

206529921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24273 (or 24270 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 206529921 is about 14371.1489102298. The cubic root of 206529921 is about 591.1000457633.

The spelling of 206529921 in words is "two hundred six million, five hundred twenty-nine thousand, nine hundred twenty-one".