21868143 has 8 divisors (see below), whose sum is σ = 31808256. Its totient is φ = 13253400.

The previous prime is 21868141. The next prime is 21868169. The reversal of 21868143 is 34186812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21868143 - 2¹ = 21868141 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 662671 = 21868143 / (2 + 1 + 8 + 6 + 8 + 1 + 4 + 3).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21868141) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 331303 + ... + 331368.

It is an arithmetic number, because the mean of its divisors is an integer number (3976032).

Almost surely, 2^21868143 is an apocalyptic number.

21868143 is a deficient number, since it is larger than the sum of its proper divisors (9940113).

21868143 is a wasteful number, since it uses less digits than its factorization.

21868143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662685.

The product of its digits is 9216, while the sum is 33.

The square root of 21868143 is about 4676.3386318786. The cubic root of 21868143 is about 279.6430101804.

The spelling of 21868143 in words is "twenty-one million, eight hundred sixty-eight thousand, one hundred forty-three".