21044051243 has 4 divisors (see below), whose sum is σ = 21252408288. Its totient is φ = 20835694200.

The previous prime is 21044051131. The next prime is 21044051269. The reversal of 21044051243 is 34215044012.

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 21044051243 - 2⁸ = 21044050987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21044011243) 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 3 ways as a sum of consecutive naturals, for example, 104178371 + ... + 104178572.

It is an arithmetic number, because the mean of its divisors is an integer number (5313102072).

Almost surely, 2^21044051243 is an apocalyptic number.

21044051243 is a deficient number, since it is larger than the sum of its proper divisors (208357045).

21044051243 is a wasteful number, since it uses less digits than its factorization.

21044051243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208357044.

The product of its (nonzero) digits is 3840, while the sum is 26.

Adding to 21044051243 its reverse (34215044012), we get a palindrome (55259095255).

The spelling of 21044051243 in words is "twenty-one billion, forty-four million, fifty-one thousand, two hundred forty-three".