204040121101021 has 4 divisors (see below), whose sum is σ = 214779074843200. Its totient is φ = 193301167358844.

The previous prime is 204040121101009. The next prime is 204040121101051. The reversal of 204040121101021 is 120101121040402.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 204040121101021 - 2³³ = 204031531166429 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19), and also a Moran number because the ratio is a prime number: 10738953742159 = 204040121101021 / (2 + 0 + 4 + 0 + 4 + 0 + 1 + 2 + 1 + 1 + 0 + 1 + 0 + 2 + 1).

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 204040121101021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204040121101051) 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, 5369476871061 + ... + 5369476871098.

It is an arithmetic number, because the mean of its divisors is an integer number (53694768710800).

Almost surely, 2^{204040121101021} is an apocalyptic number.

It is an amenable number.

204040121101021 is a deficient number, since it is larger than the sum of its proper divisors (10738953742179).

204040121101021 is a wasteful number, since it uses less digits than its factorization.

204040121101021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10738953742178.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 204040121101021 its reverse (120101121040402), we get a palindrome (324141242141423).

The spelling of 204040121101021 in words is "two hundred four trillion, forty billion, one hundred twenty-one million, one hundred one thousand, twenty-one".