20659643 has 8 divisors (see below), whose sum is σ = 20911680. Its totient is φ = 20409480.

The previous prime is 20659627. The next prime is 20659697. The reversal of 20659643 is 34695602.

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 20659643 - 2⁴ = 20659627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20659603) 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 7 ways as a sum of consecutive naturals, for example, 37496 + ... + 38042.

It is an arithmetic number, because the mean of its divisors is an integer number (2613960).

Almost surely, 2^20659643 is an apocalyptic number.

20659643 is a deficient number, since it is larger than the sum of its proper divisors (252037).

20659643 is a wasteful number, since it uses less digits than its factorization.

20659643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 937.

The product of its (nonzero) digits is 38880, while the sum is 35.

The square root of 20659643 is about 4545.2879996761. The cubic root of 20659643 is about 274.3937852930.

The spelling of 20659643 in words is "twenty million, six hundred fifty-nine thousand, six hundred forty-three".