21183744643 has 16 divisors (see below), whose sum is σ = 21906402336. Its totient is φ = 20469265920.

The previous prime is 21183744619. The next prime is 21183744649. The reversal of 21183744643 is 34644738112.

It is a cyclic number.

It is not a de Polignac number, because 21183744643 - 2⁵ = 21183744611 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21183744643.

It is not an unprimeable number, because it can be changed into a prime (21183744649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9939688 + ... + 9941818.

It is an arithmetic number, because the mean of its divisors is an integer number (1369150146).

Almost surely, 2^21183744643 is an apocalyptic number.

21183744643 is a deficient number, since it is larger than the sum of its proper divisors (722657693).

21183744643 is a wasteful number, since it uses less digits than its factorization.

21183744643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3894.

The product of its digits is 387072, while the sum is 43.

The spelling of 21183744643 in words is "twenty-one billion, one hundred eighty-three million, seven hundred forty-four thousand, six hundred forty-three".