205134921 has 12 divisors (see below), whose sum is σ = 299361972. Its totient is φ = 135346176.

The previous prime is 205134911. The next prime is 205134947. The reversal of 205134921 is 129431502.

It can be written as a sum of positive squares in 2 ways, for example, as 32080896 + 173054025 = 5664^2 + 13155^2 .

It is not a de Polignac number, because 205134921 - 2⁷ = 205134793 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (205134911) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 116616 + ... + 118361.

It is an arithmetic number, because the mean of its divisors is an integer number (24946831).

Almost surely, 2^205134921 is an apocalyptic number.

It is an amenable number.

205134921 is a deficient number, since it is larger than the sum of its proper divisors (94227051).

205134921 is a wasteful number, since it uses less digits than its factorization.

205134921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235080 (or 235077 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 205134921 is about 14322.5319339843. The cubic root of 205134921 is about 589.7661823668.

The spelling of 205134921 in words is "two hundred five million, one hundred thirty-four thousand, nine hundred twenty-one".