20640204 has 96 divisors (see below), whose sum is σ = 58815680. Its totient is φ = 6220800.

The previous prime is 20640181. The next prime is 20640233. The reversal of 20640204 is 40204602.

20640204 is a `hidden beast` number, since 2 + 0 + 640 + 20 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 85524 + ... + 85764.

Almost surely, 2^20640204 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20640204, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29407840).

20640204 is an abundant number, since it is smaller than the sum of its proper divisors (38175476).

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

20640204 is a wasteful number, since it uses less digits than its factorization.

20640204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 328 (or 320 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 20640204 is about 4543.1491280829. The cubic root of 20640204 is about 274.3076977358.

Adding to 20640204 its reverse (40204602), we get a palindrome (60844806).

The spelling of 20640204 in words is "twenty million, six hundred forty thousand, two hundred four".