21221143 has 8 divisors (see below), whose sum is σ = 21962880. Its totient is φ = 20483040.

The previous prime is 21221131. The next prime is 21221153. The reversal of 21221143 is 34112212.

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

It is a cyclic number.

It is not a de Polignac number, because 21221143 - 2⁹ = 21220631 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221113) 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, 16653 + ... + 17881.

It is an arithmetic number, because the mean of its divisors is an integer number (2745360).

Almost surely, 2^21221143 is an apocalyptic number.

21221143 is a deficient number, since it is larger than the sum of its proper divisors (741737).

21221143 is a wasteful number, since it uses less digits than its factorization.

21221143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1817.

The product of its digits is 96, while the sum is 16.

The square root of 21221143 is about 4606.6411842035. The cubic root of 21221143 is about 276.8574772816.

Adding to 21221143 its reverse (34112212), we get a palindrome (55333355).

The spelling of 21221143 in words is "twenty-one million, two hundred twenty-one thousand, one hundred forty-three".