205128901 has 4 divisors (see below), whose sum is σ = 205157952. Its totient is φ = 205099852.

The previous prime is 205128893. The next prime is 205128923. The reversal of 205128901 is 109821502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 205128901 - 2³ = 205128893 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 205128901.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205128941) by changing a digit.

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, 3636 + ... + 20578.

It is an arithmetic number, because the mean of its divisors is an integer number (51289488).

Almost surely, 2^205128901 is an apocalyptic number.

It is an amenable number.

205128901 is a deficient number, since it is larger than the sum of its proper divisors (29051).

205128901 is a wasteful number, since it uses less digits than its factorization.

205128901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29050.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 205128901 is about 14322.3217740700. The cubic root of 205128901 is about 589.7604131116.

The spelling of 205128901 in words is "two hundred five million, one hundred twenty-eight thousand, nine hundred one".