21310543 has 4 divisors (see below), whose sum is σ = 21340120. Its totient is φ = 21280968.

The previous prime is 21310519. The next prime is 21310561. The reversal of 21310543 is 34501312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21310543 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21310543.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21310043) 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, 13680 + ... + 15157.

It is an arithmetic number, because the mean of its divisors is an integer number (5335030).

Almost surely, 2^21310543 is an apocalyptic number.

21310543 is a deficient number, since it is larger than the sum of its proper divisors (29577).

21310543 is an equidigital number, since it uses as much as digits as its factorization.

21310543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29576.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21310543 is about 4616.3343683057. The cubic root of 21310543 is about 277.2457124593.

Adding to 21310543 its reverse (34501312), we get a palindrome (55811855).

The spelling of 21310543 in words is "twenty-one million, three hundred ten thousand, five hundred forty-three".