21331320121 has 8 divisors (see below), whose sum is σ = 22516574400. Its totient is φ = 20152321200.

The previous prime is 21331320079. The next prime is 21331320137. The reversal of 21331320121 is 12102313312.

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 21331320121 - 2²⁵ = 21297765689 is a prime.

It is a super-4 number, since 4×21331320121⁴ (a number of 42 digits) contains 4444 as substring.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21331320191) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1556830 + ... + 1570471.

It is an arithmetic number, because the mean of its divisors is an integer number (2814571800).

Almost surely, 2^21331320121 is an apocalyptic number.

It is an amenable number.

21331320121 is a deficient number, since it is larger than the sum of its proper divisors (1185254279).

21331320121 is a wasteful number, since it uses less digits than its factorization.

21331320121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3127679.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21331320121 its reverse (12102313312), we get a palindrome (33433633433).

The spelling of 21331320121 in words is "twenty-one billion, three hundred thirty-one million, three hundred twenty thousand, one hundred twenty-one".