204321121791 has 4 divisors (see below), whose sum is σ = 272428162392. Its totient is φ = 136214081192.

The previous prime is 204321121639. The next prime is 204321121811. The reversal of 204321121791 is 197121123402.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 204321121791 - 2¹⁰ = 204321120767 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204321121591) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34053520296 + ... + 34053520301.

It is an arithmetic number, because the mean of its divisors is an integer number (68107040598).

Almost surely, 2^204321121791 is an apocalyptic number.

204321121791 is a deficient number, since it is larger than the sum of its proper divisors (68107040601).

204321121791 is an equidigital number, since it uses as much as digits as its factorization.

204321121791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68107040600.

The product of its (nonzero) digits is 6048, while the sum is 33.

The spelling of 204321121791 in words is "two hundred four billion, three hundred twenty-one million, one hundred twenty-one thousand, seven hundred ninety-one".