20644036 has 12 divisors (see below), whose sum is σ = 41288128. Its totient is φ = 8847432.

The previous prime is 20644007. The next prime is 20644037. The reversal of 20644036 is 63044602.

20644036 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 20644036.

It is not an unprimeable number, because it can be changed into a prime (20644037) 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, 368616 + ... + 368671.

Almost surely, 2^20644036 is an apocalyptic number.

It is an amenable number.

20644036 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

20644036 is a wasteful number, since it uses less digits than its factorization.

20644036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 737298 (or 737296 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 25.

The square root of 20644036 is about 4543.5708424102. The cubic root of 20644036 is about 274.3246724074.

Adding to 20644036 its reverse (63044602), we get a palindrome (83688638).

The spelling of 20644036 in words is "twenty million, six hundred forty-four thousand, thirty-six".