20728255 has 8 divisors (see below), whose sum is σ = 24904224. Its totient is φ = 16562400.

The previous prime is 20728249. The next prime is 20728271. The reversal of 20728255 is 55282702.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-20728255 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3145 + ... + 7165.

It is an arithmetic number, because the mean of its divisors is an integer number (3113028).

Almost surely, 2^20728255 is an apocalyptic number.

20728255 is a deficient number, since it is larger than the sum of its proper divisors (4175969).

20728255 is a wasteful number, since it uses less digits than its factorization.

20728255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5057.

The product of its (nonzero) digits is 11200, while the sum is 31.

The square root of 20728255 is about 4552.8293400917. The cubic root of 20728255 is about 274.6972094325.

The spelling of 20728255 in words is "twenty million, seven hundred twenty-eight thousand, two hundred fifty-five".