20728430 has 16 divisors (see below), whose sum is σ = 39275280. Its totient is φ = 7854912.

The previous prime is 20728427. The next prime is 20728439. The reversal of 20728430 is 3482702.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20728430.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20728439) 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 7 ways as a sum of consecutive naturals, for example, 54359 + ... + 54738.

It is an arithmetic number, because the mean of its divisors is an integer number (2454705).

Almost surely, 2^20728430 is an apocalyptic number.

20728430 is a deficient number, since it is larger than the sum of its proper divisors (18546850).

20728430 is a wasteful number, since it uses less digits than its factorization.

20728430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109123.

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 20728430 is about 4552.8485588695. The cubic root of 20728430 is about 274.6979824816.

The spelling of 20728430 in words is "twenty million, seven hundred twenty-eight thousand, four hundred thirty".