205447421 has 16 divisors (see below), whose sum is σ = 217694400. Its totient is φ = 193632768.

The previous prime is 205447409. The next prime is 205447441. The reversal of 205447421 is 124744502.

It is a cyclic number.

It is not a de Polignac number, because 205447421 - 2⁶ = 205447357 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205447441) 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 15 ways as a sum of consecutive naturals, for example, 220685 + ... + 221613.

It is an arithmetic number, because the mean of its divisors is an integer number (13605900).

Almost surely, 2^205447421 is an apocalyptic number.

It is an amenable number.

205447421 is a deficient number, since it is larger than the sum of its proper divisors (12246979).

205447421 is a wasteful number, since it uses less digits than its factorization.

205447421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1148.

The product of its (nonzero) digits is 8960, while the sum is 29.

The square root of 205447421 is about 14333.4371662906. The cubic root of 205447421 is about 590.0655112548.

The spelling of 205447421 in words is "two hundred five million, four hundred forty-seven thousand, four hundred twenty-one".