204435021 has 16 divisors (see below), whose sum is σ = 311721984. Its totient is φ = 116744304.

The previous prime is 204435001. The next prime is 204435031. The reversal of 204435021 is 120534402.

It is not a de Polignac number, because 204435021 - 2⁶ = 204434957 is a prime.

It is a super-2 number, since 2×204435021² = 83587355622540882, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204435001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54616 + ... + 58238.

It is an arithmetic number, because the mean of its divisors is an integer number (19482624).

Almost surely, 2^204435021 is an apocalyptic number.

204435021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

204435021 is a deficient number, since it is larger than the sum of its proper divisors (107286963).

204435021 is a wasteful number, since it uses less digits than its factorization.

204435021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6320.

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 204435021 is about 14298.0775281154. The cubic root of 204435021 is about 589.0946768479.

Adding to 204435021 its reverse (120534402), we get a palindrome (324969423).

The spelling of 204435021 in words is "two hundred four million, four hundred thirty-five thousand, twenty-one".