20728375 has 16 divisors (see below), whose sum is σ = 26076960. Its totient is φ = 16449600.

The previous prime is 20728339. The next prime is 20728387. The reversal of 20728375 is 57382702.

It is a de Polignac number, because none of the positive numbers 2^k-20728375 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20728375.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 16779 + ... + 17971.

It is an arithmetic number, because the mean of its divisors is an integer number (1629810).

Almost surely, 2^20728375 is an apocalyptic number.

20728375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20728375 is a deficient number, since it is larger than the sum of its proper divisors (5348585).

20728375 is a wasteful number, since it uses less digits than its factorization.

20728375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1347 (or 1337 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 34.

The square root of 20728375 is about 4552.8425186909. The cubic root of 20728375 is about 274.6977395238.

It can be divided in two parts, 207 and 28375, that added together give a palindrome (28582).

The spelling of 20728375 in words is "twenty million, seven hundred twenty-eight thousand, three hundred seventy-five".