20650643 has 4 divisors (see below), whose sum is σ = 22239168. Its totient is φ = 19062120.

The previous prime is 20650607. The next prime is 20650657. The reversal of 20650643 is 34605602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34605602 = 2 ⋅17302801.

It is a cyclic number.

It is not a de Polignac number, because 20650643 - 2⁶ = 20650579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20650603) 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, 794243 + ... + 794268.

It is an arithmetic number, because the mean of its divisors is an integer number (5559792).

Almost surely, 2^20650643 is an apocalyptic number.

20650643 is a deficient number, since it is larger than the sum of its proper divisors (1588525).

20650643 is a wasteful number, since it uses less digits than its factorization.

20650643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1588524.

The product of its (nonzero) digits is 4320, while the sum is 26.

The square root of 20650643 is about 4544.2978555548. The cubic root of 20650643 is about 274.3539346083.

The spelling of 20650643 in words is "twenty million, six hundred fifty thousand, six hundred forty-three".