20686728 has 16 divisors (see below), whose sum is σ = 51716880. Its totient is φ = 6895568.

The previous prime is 20686727. The next prime is 20686733. The reversal of 20686728 is 82768602.

It is not an unprimeable number, because it can be changed into a prime (20686723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 430950 + ... + 430997.

It is an arithmetic number, because the mean of its divisors is an integer number (3232305).

Almost surely, 2^20686728 is an apocalyptic number.

It is an amenable number.

20686728 is an abundant number, since it is smaller than the sum of its proper divisors (31030152).

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

20686728 is a wasteful number, since it uses less digits than its factorization.

20686728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 861956 (or 861952 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 39.

The square root of 20686728 is about 4548.2664829581. The cubic root of 20686728 is about 274.5136439348.

The spelling of 20686728 in words is "twenty million, six hundred eighty-six thousand, seven hundred twenty-eight".