21042566603 has 4 divisors (see below), whose sum is σ = 21042997800. Its totient is φ = 21042135408.

The previous prime is 21042566593. The next prime is 21042566639. The reversal of 21042566603 is 30666524012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21042566603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21042566683) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131450 + ... + 243647.

It is an arithmetic number, because the mean of its divisors is an integer number (5260749450).

Almost surely, 2^21042566603 is an apocalyptic number.

21042566603 is a deficient number, since it is larger than the sum of its proper divisors (431197).

21042566603 is an equidigital number, since it uses as much as digits as its factorization.

21042566603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431196.

The product of its (nonzero) digits is 51840, while the sum is 35.

The spelling of 21042566603 in words is "twenty-one billion, forty-two million, five hundred sixty-six thousand, six hundred three".