21225543 has 8 divisors (see below), whose sum is σ = 28465008. Its totient is φ = 14068224.

The previous prime is 21225541. The next prime is 21225551. The reversal of 21225543 is 34552212.

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

It is not a de Polignac number, because 21225543 - 2¹ = 21225541 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21225541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19930 + ... + 20967.

It is an arithmetic number, because the mean of its divisors is an integer number (3558126).

Almost surely, 2^21225543 is an apocalyptic number.

21225543 is a deficient number, since it is larger than the sum of its proper divisors (7239465).

21225543 is a wasteful number, since it uses less digits than its factorization.

21225543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41073.

The product of its digits is 2400, while the sum is 24.

The square root of 21225543 is about 4607.1187308338. The cubic root of 21225543 is about 276.8766105381.

Adding to 21225543 its reverse (34552212), we get a palindrome (55777755).

The spelling of 21225543 in words is "twenty-one million, two hundred twenty-five thousand, five hundred forty-three".