20728167 has 4 divisors (see below), whose sum is σ = 27637560. Its totient is φ = 13818776.

The previous prime is 20728159. The next prime is 20728199. The reversal of 20728167 is 76182702.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20728167 - 2³ = 20728159 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20728067) 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 3 ways as a sum of consecutive naturals, for example, 3454692 + ... + 3454697.

It is an arithmetic number, because the mean of its divisors is an integer number (6909390).

Almost surely, 2^20728167 is an apocalyptic number.

20728167 is a deficient number, since it is larger than the sum of its proper divisors (6909393).

20728167 is an equidigital number, since it uses as much as digits as its factorization.

20728167 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6909392.

The product of its (nonzero) digits is 9408, while the sum is 33.

The square root of 20728167 is about 4552.8196757614. The cubic root of 20728167 is about 274.6968206976.

The spelling of 20728167 in words is "twenty million, seven hundred twenty-eight thousand, one hundred sixty-seven".