20668843 has 4 divisors (see below), whose sum is σ = 22258768. Its totient is φ = 19078920.

The previous prime is 20668841. The next prime is 20668859. The reversal of 20668843 is 34886602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34886602 = 2 ⋅17443301.

It is a cyclic number.

It is not a de Polignac number, because 20668843 - 2¹ = 20668841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20668841) 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, 794943 + ... + 794968.

It is an arithmetic number, because the mean of its divisors is an integer number (5564692).

Almost surely, 2^20668843 is an apocalyptic number.

20668843 is a deficient number, since it is larger than the sum of its proper divisors (1589925).

20668843 is a wasteful number, since it uses less digits than its factorization.

20668843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1589924.

The product of its (nonzero) digits is 55296, while the sum is 37.

The square root of 20668843 is about 4546.2999241141. The cubic root of 20668843 is about 274.4345095882.

The spelling of 20668843 in words is "twenty million, six hundred sixty-eight thousand, eight hundred forty-three".