21240343 has 8 divisors (see below), whose sum is σ = 21531312. Its totient is φ = 20951616.

The previous prime is 21240313. The next prime is 21240377. The reversal of 21240343 is 34304212.

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 21240343 - 2⁵ = 21240311 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21240343.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21240313) 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, 26596 + ... + 27382.

It is an arithmetic number, because the mean of its divisors is an integer number (2691414).

Almost surely, 2^21240343 is an apocalyptic number.

21240343 is a deficient number, since it is larger than the sum of its proper divisors (290969).

21240343 is a wasteful number, since it uses less digits than its factorization.

21240343 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1121.

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 21240343 is about 4608.7246609013. The cubic root of 21240343 is about 276.9409484569.

Adding to 21240343 its reverse (34304212), we get a palindrome (55544555).

The spelling of 21240343 in words is "twenty-one million, two hundred forty thousand, three hundred forty-three".