204423501421 has 4 divisors (see below), whose sum is σ = 204503701500. Its totient is φ = 204343301344.

The previous prime is 204423501397. The next prime is 204423501437. The reversal of 204423501421 is 124105324402.

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

It can be written as a sum of positive squares in 2 ways, for example, as 194331088900 + 10092412521 = 440830^2 + 100461^2 .

It is a cyclic number.

It is not a de Polignac number, because 204423501421 - 2¹³ = 204423493229 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 204423501421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204423504421) 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, 40096216 + ... + 40101313.

It is an arithmetic number, because the mean of its divisors is an integer number (51125925375).

Almost surely, 2^204423501421 is an apocalyptic number.

It is an amenable number.

204423501421 is a deficient number, since it is larger than the sum of its proper divisors (80200079).

204423501421 is an equidigital number, since it uses as much as digits as its factorization.

204423501421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80200078.

The product of its (nonzero) digits is 7680, while the sum is 28.

Adding to 204423501421 its reverse (124105324402), we get a palindrome (328528825823).

The spelling of 204423501421 in words is "two hundred four billion, four hundred twenty-three million, five hundred one thousand, four hundred twenty-one".