20643589 has 4 divisors (see below), whose sum is σ = 20656800. Its totient is φ = 20630380.

The previous prime is 20643587. The next prime is 20643611. The reversal of 20643589 is 98534602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20643589 - 2¹ = 20643587 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 (20643587) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3889 + ... + 7510.

It is an arithmetic number, because the mean of its divisors is an integer number (5164200).

Almost surely, 2^20643589 is an apocalyptic number.

It is an amenable number.

20643589 is a deficient number, since it is larger than the sum of its proper divisors (13211).

20643589 is a wasteful number, since it uses less digits than its factorization.

20643589 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13210.

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 20643589 is about 4543.5216517587. The cubic root of 20643589 is about 274.3226924326.

The spelling of 20643589 in words is "twenty million, six hundred forty-three thousand, five hundred eighty-nine".