205121403 has 12 divisors (see below), whose sum is σ = 307260408. Its totient is φ = 136747440.

The previous prime is 205121393. The next prime is 205121419. The reversal of 205121403 is 304121502.

It is not a de Polignac number, because 205121403 - 2⁴ = 205121387 is a prime.

It is not an unprimeable number, because it can be changed into a prime (205121443) 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, 421818 + ... + 422303.

It is an arithmetic number, because the mean of its divisors is an integer number (25605034).

Almost surely, 2^205121403 is an apocalyptic number.

205121403 is a deficient number, since it is larger than the sum of its proper divisors (102139005).

205121403 is an frugal number, since it uses more digits than its factorization.

205121403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 844136 (or 844124 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 205121403 is about 14322.0600124423. The cubic root of 205121403 is about 589.7532272601.

Adding to 205121403 its reverse (304121502), we get a palindrome (509242905).

Subtracting 205121403 from its reverse (304121502), we obtain a palindrome (99000099).

The spelling of 205121403 in words is "two hundred five million, one hundred twenty-one thousand, four hundred three".