21124743 has 8 divisors (see below), whose sum is σ = 28927728. Its totient is φ = 13702464.

The previous prime is 21124711. The next prime is 21124759. The reversal of 21124743 is 34742112.

It is a happy number.

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

It is not a de Polignac number, because 21124743 - 2⁵ = 21124711 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21124703) 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, 95046 + ... + 95267.

It is an arithmetic number, because the mean of its divisors is an integer number (3615966).

Almost surely, 2^21124743 is an apocalyptic number.

21124743 is a deficient number, since it is larger than the sum of its proper divisors (7802985).

21124743 is a wasteful number, since it uses less digits than its factorization.

21124743 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190353.

The product of its digits is 1344, while the sum is 24.

The square root of 21124743 is about 4596.1661197133. The cubic root of 21124743 is about 276.4376196576.

Adding to 21124743 its reverse (34742112), we get a palindrome (55866855).

The spelling of 21124743 in words is "twenty-one million, one hundred twenty-four thousand, seven hundred forty-three".