21003335643 has 8 divisors (see below), whose sum is σ = 28005779968. Its totient is φ = 14001557544.

The previous prime is 21003335629. The next prime is 21003335653. The reversal of 21003335643 is 34653330012.

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

It is not a de Polignac number, because 21003335643 - 2¹⁰ = 21003334619 is a prime.

It is a super-2 number, since 2×21003335643² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21003335643.

It is not an unprimeable number, because it can be changed into a prime (21003335653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 87655 + ... + 222912.

It is an arithmetic number, because the mean of its divisors is an integer number (3500722496).

Almost surely, 2^21003335643 is an apocalyptic number.

21003335643 is a deficient number, since it is larger than the sum of its proper divisors (7002444325).

21003335643 is a wasteful number, since it uses less digits than its factorization.

21003335643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333113.

The product of its (nonzero) digits is 19440, while the sum is 30.

Adding to 21003335643 its reverse (34653330012), we get a palindrome (55656665655).

The spelling of 21003335643 in words is "twenty-one billion, three million, three hundred thirty-five thousand, six hundred forty-three".