21003066503 has 4 divisors (see below), whose sum is σ = 21004446528. Its totient is φ = 21001686480.

The previous prime is 21003066481. The next prime is 21003066527. The reversal of 21003066503 is 30566030012.

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 21003066503 - 2⁶ = 21003066439 is a prime.

It is a super-2 number, since 2×21003066503² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003066703) 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, 666926 + ... + 697707.

It is an arithmetic number, because the mean of its divisors is an integer number (5251111632).

Almost surely, 2^21003066503 is an apocalyptic number.

21003066503 is a deficient number, since it is larger than the sum of its proper divisors (1380025).

21003066503 is a wasteful number, since it uses less digits than its factorization.

21003066503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1380024.

The product of its (nonzero) digits is 3240, while the sum is 26.

Adding to 21003066503 its reverse (30566030012), we get a palindrome (51569096515).

It can be divided in two parts, 2100 and 3066503, that added together give a palindrome (3068603).

The spelling of 21003066503 in words is "twenty-one billion, three million, sixty-six thousand, five hundred three".