21735143 has 4 divisors (see below), whose sum is σ = 21745920. Its totient is φ = 21724368.

The previous prime is 21735139. The next prime is 21735149. The reversal of 21735143 is 34153712.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21735143 - 2² = 21735139 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21735149) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1358 + ... + 6731.

It is an arithmetic number, because the mean of its divisors is an integer number (5436480).

Almost surely, 2^21735143 is an apocalyptic number.

21735143 is a deficient number, since it is larger than the sum of its proper divisors (10777).

21735143 is an equidigital number, since it uses as much as digits as its factorization.

21735143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10776.

The product of its digits is 2520, while the sum is 26.

The square root of 21735143 is about 4662.0964168494. The cubic root of 21735143 is about 279.0749360854.

Adding to 21735143 its reverse (34153712), we get a palindrome (55888855).

The spelling of 21735143 in words is "twenty-one million, seven hundred thirty-five thousand, one hundred forty-three".