20779728 has 40 divisors (see below), whose sum is σ = 54246528. Its totient is φ = 6853632.

The previous prime is 20779727. The next prime is 20779739. The reversal of 20779728 is 82797702.

It is a self number, because there is not a number n which added to its sum of digits gives 20779728.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20779723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2425 + ... + 6887.

Almost surely, 2^20779728 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 20779728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27123264).

20779728 is an abundant number, since it is smaller than the sum of its proper divisors (33466800).

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

20779728 is a wasteful number, since it uses less digits than its factorization.

20779728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4571 (or 4565 counting only the distinct ones).

The product of its (nonzero) digits is 98784, while the sum is 42.

The square root of 20779728 is about 4558.4786935994. The cubic root of 20779728 is about 274.9244001555.

The spelling of 20779728 in words is "twenty million, seven hundred seventy-nine thousand, seven hundred twenty-eight".