20728215 has 12 divisors (see below), whose sum is σ = 35928984. Its totient is φ = 11055024.

The previous prime is 20728199. The next prime is 20728217. The reversal of 20728215 is 51282702.

It is not a de Polignac number, because 20728215 - 2⁴ = 20728199 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20728217) 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 11 ways as a sum of consecutive naturals, for example, 230269 + ... + 230358.

It is an arithmetic number, because the mean of its divisors is an integer number (2994082).

Almost surely, 2^20728215 is an apocalyptic number.

20728215 is a deficient number, since it is larger than the sum of its proper divisors (15200769).

20728215 is a wasteful number, since it uses less digits than its factorization.

20728215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 460638 (or 460635 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 20728215 is about 4552.8249472168. The cubic root of 20728215 is about 274.6970327350.

The spelling of 20728215 in words is "twenty million, seven hundred twenty-eight thousand, two hundred fifteen".