20661204 has 12 divisors (see below), whose sum is σ = 48209504. Its totient is φ = 6887064.

The previous prime is 20661203. The next prime is 20661233. The reversal of 20661204 is 40216602.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20661203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 860872 + ... + 860895.

Almost surely, 2^20661204 is an apocalyptic number.

It is an amenable number.

20661204 is an abundant number, since it is smaller than the sum of its proper divisors (27548300).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20661204 is a wasteful number, since it uses less digits than its factorization.

20661204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1721774 (or 1721772 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 20661204 is about 4545.4597127243. The cubic root of 20661204 is about 274.4006959951.

Adding to 20661204 its reverse (40216602), we get a palindrome (60877806).

The spelling of 20661204 in words is "twenty million, six hundred sixty-one thousand, two hundred four".