21220543 has 8 divisors (see below), whose sum is σ = 21835088. Its totient is φ = 20611584.

The previous prime is 21220531. The next prime is 21220583. The reversal of 21220543 is 34502212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21220543 is a prime.

It is a super-2 number, since 2×21220543² = 900622890429698, which contains 22 as substring.

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 21220543.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220583) 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, 7021 + ... + 9577.

It is an arithmetic number, because the mean of its divisors is an integer number (2729386).

Almost surely, 2^21220543 is an apocalyptic number.

21220543 is a deficient number, since it is larger than the sum of its proper divisors (614545).

21220543 is a wasteful number, since it uses less digits than its factorization.

21220543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2793.

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 21220543 is about 4606.5760603728. The cubic root of 21220543 is about 276.8548679963.

Adding to 21220543 its reverse (34502212), we get a palindrome (55722755).

The spelling of 21220543 in words is "twenty-one million, two hundred twenty thousand, five hundred forty-three".