21321111021 has 32 divisors (see below), whose sum is σ = 34017822720. Its totient is φ = 11613923904.

The previous prime is 21321110957. The next prime is 21321111047. The reversal of 21321111021 is 12011112312.

It is not a de Polignac number, because 21321111021 - 2⁶ = 21321110957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321121021) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 66190 + ... + 216848.

It is an arithmetic number, because the mean of its divisors is an integer number (1063056960).

Almost surely, 2^21321111021 is an apocalyptic number.

21321111021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21321111021 is a deficient number, since it is larger than the sum of its proper divisors (12696711699).

21321111021 is a wasteful number, since it uses less digits than its factorization.

21321111021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150985.

The product of its (nonzero) digits is 24, while the sum is 15.

Adding to 21321111021 its reverse (12011112312), we get a palindrome (33332223333).

The spelling of 21321111021 in words is "twenty-one billion, three hundred twenty-one million, one hundred eleven thousand, twenty-one".