21121030021 has 96 divisors (see below), whose sum is σ = 28483584000. Its totient is φ = 15602932800.

The previous prime is 21121030001. The next prime is 21121030031. The reversal of 21121030021 is 12003012112.

It is not a de Polignac number, because 21121030021 - 2⁷ = 21121029893 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a junction number, because it is equal to n+sod(n) for n = 21121029983 and 21121030010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121030001) 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 95 ways as a sum of consecutive naturals, for example, 139874296 + ... + 139874446.

It is an arithmetic number, because the mean of its divisors is an integer number (296704000).

Almost surely, 2^21121030021 is an apocalyptic number.

It is an amenable number.

21121030021 is a deficient number, since it is larger than the sum of its proper divisors (7362553979).

21121030021 is a wasteful number, since it uses less digits than its factorization.

21121030021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344 (or 317 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21121030021 its reverse (12003012112), we get a palindrome (33124042133).

The spelling of 21121030021 in words is "twenty-one billion, one hundred twenty-one million, thirty thousand, twenty-one".