20721044 has 12 divisors (see below), whose sum is σ = 36435168. Its totient is φ = 10311000.

The previous prime is 20721037. The next prime is 20721047. The reversal of 20721044 is 44012702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20721047) 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, 11432 + ... + 13119.

It is an arithmetic number, because the mean of its divisors is an integer number (3036264).

Almost surely, 2^20721044 is an apocalyptic number.

It is an amenable number.

20721044 is a deficient number, since it is larger than the sum of its proper divisors (15714124).

20721044 is a wasteful number, since it uses less digits than its factorization.

20721044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24766 (or 24764 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 20.

The square root of 20721044 is about 4552.0373460682. The cubic root of 20721044 is about 274.6653516082.

Adding to 20721044 its reverse (44012702), we get a palindrome (64733746).

The spelling of 20721044 in words is "twenty million, seven hundred twenty-one thousand, forty-four".