20785643 has 8 divisors (see below), whose sum is σ = 21058800. Its totient is φ = 20514528.

The previous prime is 20785631. The next prime is 20785669. The reversal of 20785643 is 34658702.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20785643 - 2⁶ = 20785579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20785613) 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, 31505 + ... + 32157.

It is an arithmetic number, because the mean of its divisors is an integer number (2632350).

Almost surely, 2^20785643 is an apocalyptic number.

20785643 is a deficient number, since it is larger than the sum of its proper divisors (273157).

20785643 is a wasteful number, since it uses less digits than its factorization.

20785643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1021.

The product of its (nonzero) digits is 40320, while the sum is 35.

The square root of 20785643 is about 4559.1274384470. The cubic root of 20785643 is about 274.9504836466.

The spelling of 20785643 in words is "twenty million, seven hundred eighty-five thousand, six hundred forty-three".