21001012003 has 16 divisors (see below), whose sum is σ = 22074020640. Its totient is φ = 19960148736.

The previous prime is 21001011947. The next prime is 21001012007. The reversal of 21001012003 is 30021010012.

It is a cyclic number.

It is not a de Polignac number, because 21001012003 - 2⁹ = 21001011491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001012007) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 234901 + ... + 311737.

It is an arithmetic number, because the mean of its divisors is an integer number (1379626290).

Almost surely, 2^21001012003 is an apocalyptic number.

21001012003 is a deficient number, since it is larger than the sum of its proper divisors (1073008637).

21001012003 is an equidigital number, since it uses as much as digits as its factorization.

21001012003 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77046.

The product of its (nonzero) digits is 12, while the sum is 10.

Adding to 21001012003 its reverse (30021010012), we get a palindrome (51022022015).

The spelling of 21001012003 in words is "twenty-one billion, one million, twelve thousand, three".