20843845 has 16 divisors (see below), whose sum is σ = 27574848. Its totient is φ = 14999040.

The previous prime is 20843843. The next prime is 20843861. The reversal of 20843845 is 54834802.

It is not a de Polignac number, because 20843845 - 2¹ = 20843843 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 20843845.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20843843) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3382 + ... + 7288.

It is an arithmetic number, because the mean of its divisors is an integer number (1723428).

Almost surely, 2^20843845 is an apocalyptic number.

It is an amenable number.

20843845 is a deficient number, since it is larger than the sum of its proper divisors (6731003).

20843845 is a wasteful number, since it uses less digits than its factorization.

20843845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4020.

The product of its (nonzero) digits is 30720, while the sum is 34.

The square root of 20843845 is about 4565.5059960534. The cubic root of 20843845 is about 275.2068746381.

It can be divided in two parts, 2084 and 3845, that added together give a square (5929 = 77²).

The spelling of 20843845 in words is "twenty million, eight hundred forty-three thousand, eight hundred forty-five".