20631728 has 20 divisors (see below), whose sum is σ = 43049328. Its totient is φ = 9522240.

The previous prime is 20631707. The next prime is 20631757. The reversal of 20631728 is 82713602.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 20631728.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 49388 + ... + 49803.

Almost surely, 2^20631728 is an apocalyptic number.

It is an amenable number.

20631728 is an abundant number, since it is smaller than the sum of its proper divisors (22417600).

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

20631728 is a wasteful number, since it uses less digits than its factorization.

20631728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99212 (or 99206 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 20631728 is about 4542.2161991697. The cubic root of 20631728 is about 274.2701439987.

The spelling of 20631728 in words is "twenty million, six hundred thirty-one thousand, seven hundred twenty-eight".