204081821 has 4 divisors (see below), whose sum is σ = 216086652. Its totient is φ = 192076992.

The previous prime is 204081817. The next prime is 204081833. The reversal of 204081821 is 128180402.

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 177156100 + 26925721 = 13310^2 + 5189^2 .

It is a cyclic number.

It is not a de Polignac number, because 204081821 - 2² = 204081817 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204081121) 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, 6002390 + ... + 6002423.

It is an arithmetic number, because the mean of its divisors is an integer number (54021663).

Almost surely, 2^204081821 is an apocalyptic number.

It is an amenable number.

204081821 is a deficient number, since it is larger than the sum of its proper divisors (12004831).

204081821 is a wasteful number, since it uses less digits than its factorization.

204081821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12004830.

The product of its (nonzero) digits is 1024, while the sum is 26.

The square root of 204081821 is about 14285.7208778556. The cubic root of 204081821 is about 588.7552239504.

The spelling of 204081821 in words is "two hundred four million, eighty-one thousand, eight hundred twenty-one".