21001023003 has 16 divisors (see below), whose sum is σ = 29029547520. Its totient is φ = 13488677664.

The previous prime is 21001022989. The next prime is 21001023023. The reversal of 21001023003 is 30032010012.

It is a happy number.

It is not a de Polignac number, because 21001023003 - 2⁹ = 21001022491 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21001023003.

It is not an unprimeable number, because it can be changed into a prime (21001023023) 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, 220401 + ... + 300962.

It is an arithmetic number, because the mean of its divisors is an integer number (1814346720).

Almost surely, 2^21001023003 is an apocalyptic number.

21001023003 is a deficient number, since it is larger than the sum of its proper divisors (8028524517).

21001023003 is a wasteful number, since it uses less digits than its factorization.

21001023003 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 521858.

The product of its (nonzero) digits is 36, while the sum is 12.

Adding to 21001023003 its reverse (30032010012), we get a palindrome (51033033015).

The spelling of 21001023003 in words is "twenty-one billion, one million, twenty-three thousand, three".