21331143 has 12 divisors (see below), whose sum is σ = 32151600. Its totient is φ = 13602336.

The previous prime is 21331133. The next prime is 21331147. The reversal of 21331143 is 34113312.

It is not a de Polignac number, because 21331143 - 2⁴ = 21331127 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331147) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 51318 + ... + 51731.

It is an arithmetic number, because the mean of its divisors is an integer number (2679300).

Almost surely, 2^21331143 is an apocalyptic number.

21331143 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21331143 is a deficient number, since it is larger than the sum of its proper divisors (10820457).

21331143 is a wasteful number, since it uses less digits than its factorization.

21331143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103078 (or 103075 counting only the distinct ones).

The product of its digits is 216, while the sum is 18.

The square root of 21331143 is about 4618.5650368919. The cubic root of 21331143 is about 277.3350175884.

Adding to 21331143 its reverse (34113312), we get a palindrome (55444455).

The spelling of 21331143 in words is "twenty-one million, three hundred thirty-one thousand, one hundred forty-three".