21561343 has 8 divisors (see below), whose sum is σ = 22298400. Its totient is φ = 20832480.

The previous prime is 21561341. The next prime is 21561347. The reversal of 21561343 is 34316512.

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

It is not a de Polignac number, because 21561343 - 2¹ = 21561341 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21561341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3558 + ... + 7468.

It is an arithmetic number, because the mean of its divisors is an integer number (2787300).

Almost surely, 2^21561343 is an apocalyptic number.

21561343 is a deficient number, since it is larger than the sum of its proper divisors (737057).

21561343 is a wasteful number, since it uses less digits than its factorization.

21561343 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4097.

The product of its digits is 2160, while the sum is 25.

The square root of 21561343 is about 4643.4193220083. The cubic root of 21561343 is about 278.3290920107.

Adding to 21561343 its reverse (34316512), we get a palindrome (55877855).

It can be divided in two parts, 21561 and 343, that added together give a square (21904 = 148²).

The spelling of 21561343 in words is "twenty-one million, five hundred sixty-one thousand, three hundred forty-three".