21321112021 has 16 divisors (see below), whose sum is σ = 23390535168. Its totient is φ = 19273820400.

The previous prime is 21321112013. The next prime is 21321112081. The reversal of 21321112021 is 12021112312.

It is a cyclic number.

It is not a de Polignac number, because 21321112021 - 2³ = 21321112013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21321111986 and 21321112004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321112081) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1645450 + ... + 1658356.

It is an arithmetic number, because the mean of its divisors is an integer number (1461908448).

Almost surely, 2^21321112021 is an apocalyptic number.

It is an amenable number.

21321112021 is a deficient number, since it is larger than the sum of its proper divisors (2069423147).

21321112021 is a wasteful number, since it uses less digits than its factorization.

21321112021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13752.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21321112021 its reverse (12021112312), we get a palindrome (33342224333).

The spelling of 21321112021 in words is "twenty-one billion, three hundred twenty-one million, one hundred twelve thousand, twenty-one".