20728567 has 4 divisors (see below), whose sum is σ = 20738776. Its totient is φ = 20718360.

The previous prime is 20728549. The next prime is 20728571. The reversal of 20728567 is 76582702.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20728567 - 2⁷ = 20728439 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20728517) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 909 + ... + 6502.

It is an arithmetic number, because the mean of its divisors is an integer number (5184694).

Almost surely, 2^20728567 is an apocalyptic number.

20728567 is a deficient number, since it is larger than the sum of its proper divisors (10209).

20728567 is an equidigital number, since it uses as much as digits as its factorization.

20728567 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10208.

The product of its (nonzero) digits is 47040, while the sum is 37.

The square root of 20728567 is about 4552.8636043703. The cubic root of 20728567 is about 274.6985876656.

The spelling of 20728567 in words is "twenty million, seven hundred twenty-eight thousand, five hundred sixty-seven".