20859647 has 4 divisors (see below), whose sum is σ = 20933640. Its totient is φ = 20785656.

The previous prime is 20859637. The next prime is 20859649. The reversal of 20859647 is 74695802.

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 20859647 - 2⁶ = 20859583 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 (20859649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36572 + ... + 37137.

It is an arithmetic number, because the mean of its divisors is an integer number (5233410).

Almost surely, 2^20859647 is an apocalyptic number.

20859647 is a deficient number, since it is larger than the sum of its proper divisors (73993).

20859647 is an equidigital number, since it uses as much as digits as its factorization.

20859647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73992.

The product of its (nonzero) digits is 120960, while the sum is 41.

The square root of 20859647 is about 4567.2362540162. The cubic root of 20859647 is about 275.2764030853.

The spelling of 20859647 in words is "twenty million, eight hundred fifty-nine thousand, six hundred forty-seven".