20728569 has 8 divisors (see below), whose sum is σ = 28016992. Its totient is φ = 13629600.

The previous prime is 20728549. The next prime is 20728571. The reversal of 20728569 is 96582702.

It is a happy number.

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

It is not a de Polignac number, because 20728569 - 2¹¹ = 20726521 is a prime.

It is a super-2 number, since 2×20728569² = 859347145575522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20728549) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47107 + ... + 47544.

It is an arithmetic number, because the mean of its divisors is an integer number (3502124).

Almost surely, 2^20728569 is an apocalyptic number.

It is an amenable number.

20728569 is a deficient number, since it is larger than the sum of its proper divisors (7288423).

20728569 is an equidigital number, since it uses as much as digits as its factorization.

20728569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94727.

The product of its (nonzero) digits is 60480, while the sum is 39.

The square root of 20728569 is about 4552.8638240123. The cubic root of 20728569 is about 274.6985965004.

The spelling of 20728569 in words is "twenty million, seven hundred twenty-eight thousand, five hundred sixty-nine".