20400728 has 16 divisors (see below), whose sum is σ = 39485760. Its totient is φ = 9871200.

The previous prime is 20400719. The next prime is 20400803. The reversal of 20400728 is 82700402.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40883 + ... + 41378.

It is an arithmetic number, because the mean of its divisors is an integer number (2467860).

Almost surely, 2^20400728 is an apocalyptic number.

It is an amenable number.

20400728 is a deficient number, since it is larger than the sum of its proper divisors (19085032).

20400728 is a wasteful number, since it uses less digits than its factorization.

20400728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82298 (or 82294 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 23.

The square root of 20400728 is about 4516.7165064901. The cubic root of 20400728 is about 273.2426918700.

The spelling of 20400728 in words is "twenty million, four hundred thousand, seven hundred twenty-eight".