205400331021 has 16 divisors (see below), whose sum is σ = 290980339200. Its totient is φ = 128878629824.

The previous prime is 205400330977. The next prime is 205400331047. The reversal of 205400331021 is 120133004502.

205400331021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 205400331021 - 2¹⁰ = 205400329997 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205400331091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6953181 + ... + 6982658.

It is an arithmetic number, because the mean of its divisors is an integer number (18186271200).

Almost surely, 2^205400331021 is an apocalyptic number.

It is an amenable number.

205400331021 is a deficient number, since it is larger than the sum of its proper divisors (85580008179).

205400331021 is an equidigital number, since it uses as much as digits as its factorization.

205400331021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13935893 (or 13935859 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

Adding to 205400331021 its reverse (120133004502), we get a palindrome (325533335523).

The spelling of 205400331021 in words is "two hundred five billion, four hundred million, three hundred thirty-one thousand, twenty-one".