21331121021 has 8 divisors (see below), whose sum is σ = 24404174400. Its totient is φ = 18264505248.

The previous prime is 21331121011. The next prime is 21331121023. The reversal of 21331121021 is 12012113312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21331121021 - 2³⁴ = 4151251837 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331121023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1602296 + ... + 1615553.

It is an arithmetic number, because the mean of its divisors is an integer number (3050521800).

Almost surely, 2^21331121021 is an apocalyptic number.

It is an amenable number.

21331121021 is a deficient number, since it is larger than the sum of its proper divisors (3073053379).

21331121021 is an equidigital number, since it uses as much as digits as its factorization.

21331121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3218803.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21331121021 its reverse (12012113312), we get a palindrome (33343234333).

The spelling of 21331121021 in words is "twenty-one billion, three hundred thirty-one million, one hundred twenty-one thousand, twenty-one".