21224743 has 4 divisors (see below), whose sum is σ = 21331600. Its totient is φ = 21117888.

The previous prime is 21224741. The next prime is 21224759. The reversal of 21224743 is 34742212.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21224743 - 2¹ = 21224741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21224741) 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, 53130 + ... + 53527.

It is an arithmetic number, because the mean of its divisors is an integer number (5332900).

Almost surely, 2^21224743 is an apocalyptic number.

21224743 is a deficient number, since it is larger than the sum of its proper divisors (106857).

21224743 is a wasteful number, since it uses less digits than its factorization.

21224743 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106856.

The product of its digits is 2688, while the sum is 25.

The square root of 21224743 is about 4607.0319078556. The cubic root of 21224743 is about 276.8731319609.

Adding to 21224743 its reverse (34742212), we get a palindrome (55966955).

The spelling of 21224743 in words is "twenty-one million, two hundred twenty-four thousand, seven hundred forty-three".