21003312021 has 4 divisors (see below), whose sum is σ = 28004416032. Its totient is φ = 14002208012.

The previous prime is 21003312007. The next prime is 21003312047. The reversal of 21003312021 is 12021330012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21003312021 - 2⁶ = 21003311957 is a prime.

It is a super-2 number, since 2×21003312021² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003312221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3500552001 + ... + 3500552006.

It is an arithmetic number, because the mean of its divisors is an integer number (7001104008).

Almost surely, 2^21003312021 is an apocalyptic number.

It is an amenable number.

21003312021 is a deficient number, since it is larger than the sum of its proper divisors (7001104011).

21003312021 is an equidigital number, since it uses as much as digits as its factorization.

21003312021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7001104010.

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21003312021 its reverse (12021330012), we get a palindrome (33024642033).

The spelling of 21003312021 in words is "twenty-one billion, three million, three hundred twelve thousand, twenty-one".