20724843 has 4 divisors (see below), whose sum is σ = 27633128. Its totient is φ = 13816560.

The previous prime is 20724841. The next prime is 20724889. The reversal of 20724843 is 34842702.

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

It is not a de Polignac number, because 20724843 - 2¹ = 20724841 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20724843.

It is not an unprimeable number, because it can be changed into a prime (20724841) 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, 3454138 + ... + 3454143.

It is an arithmetic number, because the mean of its divisors is an integer number (6908282).

Almost surely, 2^20724843 is an apocalyptic number.

20724843 is a deficient number, since it is larger than the sum of its proper divisors (6908285).

20724843 is an equidigital number, since it uses as much as digits as its factorization.

20724843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6908284.

The product of its (nonzero) digits is 10752, while the sum is 30.

The square root of 20724843 is about 4552.4546126238. The cubic root of 20724843 is about 274.6821363144.

The spelling of 20724843 in words is "twenty million, seven hundred twenty-four thousand, eight hundred forty-three".