21203565568 has 44 divisors (see below), whose sum is σ = 43372245400. Its totient is φ = 10355208192.

The previous prime is 21203565517. The next prime is 21203565569. The reversal of 21203565568 is 86556530212.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203565569) 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 3 ways as a sum of consecutive naturals, for example, 196743 + ... + 284806.

It is an arithmetic number, because the mean of its divisors is an integer number (985732850).

Almost surely, 2^21203565568 is an apocalyptic number.

It is an amenable number.

21203565568 is an abundant number, since it is smaller than the sum of its proper divisors (22168679832).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21203565568 is an equidigital number, since it uses as much as digits as its factorization.

21203565568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 481612 (or 481594 counting only the distinct ones).

The product of its (nonzero) digits is 432000, while the sum is 43.

The spelling of 21203565568 in words is "twenty-one billion, two hundred three million, five hundred sixty-five thousand, five hundred sixty-eight".