20842843 has 4 divisors (see below), whose sum is σ = 23820400. Its totient is φ = 17865288.

The previous prime is 20842837. The next prime is 20842847. The reversal of 20842843 is 34824802.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 20842843 - 2¹³ = 20834651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20842847) 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, 1488768 + ... + 1488781.

It is an arithmetic number, because the mean of its divisors is an integer number (5955100).

Almost surely, 2^20842843 is an apocalyptic number.

20842843 is a deficient number, since it is larger than the sum of its proper divisors (2977557).

20842843 is an equidigital number, since it uses as much as digits as its factorization.

20842843 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2977556.

The product of its (nonzero) digits is 12288, while the sum is 31.

The square root of 20842843 is about 4565.3962588148. The cubic root of 20842843 is about 275.2024646759.

The spelling of 20842843 in words is "twenty million, eight hundred forty-two thousand, eight hundred forty-three".