20449728 has 84 divisors (see below), whose sum is σ = 63147448. Its totient is φ = 6289920.

The previous prime is 20449697. The next prime is 20449753. The reversal of 20449728 is 82794402.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 20449692 and 20449701.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6123 + ... + 8853.

Almost surely, 2^20449728 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 20449728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31573724).

20449728 is an abundant number, since it is smaller than the sum of its proper divisors (42697720).

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

20449728 is a wasteful number, since it uses less digits than its factorization.

20449728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2762 (or 2749 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The square root of 20449728 is about 4522.1375476648. The cubic root of 20449728 is about 273.4612818913.

The spelling of 20449728 in words is "twenty million, four hundred forty-nine thousand, seven hundred twenty-eight".