21854643 has 16 divisors (see below), whose sum is σ = 29742336. Its totient is φ = 14271840.

The previous prime is 21854641. The next prime is 21854687. The reversal of 21854643 is 34645812.

It is not a de Polignac number, because 21854643 - 2¹ = 21854641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21854641) 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, 32733 + ... + 33393.

It is an arithmetic number, because the mean of its divisors is an integer number (1858896).

Almost surely, 2^21854643 is an apocalyptic number.

21854643 is a deficient number, since it is larger than the sum of its proper divisors (7887693).

21854643 is a wasteful number, since it uses less digits than its factorization.

21854643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 874.

The product of its digits is 23040, while the sum is 33.

The square root of 21854643 is about 4674.8949720823. The cubic root of 21854643 is about 279.5854537347.

The spelling of 21854643 in words is "twenty-one million, eight hundred fifty-four thousand, six hundred forty-three".