21233100021 has 16 divisors (see below), whose sum is σ = 32364659328. Its totient is φ = 12129652800.

The previous prime is 21233100017. The next prime is 21233100043. The reversal of 21233100021 is 12000133212.

It is not a de Polignac number, because 21233100021 - 2² = 21233100017 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21233100061) 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, 73390 + ... + 218751.

It is an arithmetic number, because the mean of its divisors is an integer number (2022791208).

Almost surely, 2^21233100021 is an apocalyptic number.

21233100021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21233100021 is a deficient number, since it is larger than the sum of its proper divisors (11131559307).

21233100021 is a wasteful number, since it uses less digits than its factorization.

21233100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295612.

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21233100021 its reverse (12000133212), we get a palindrome (33233233233).

The spelling of 21233100021 in words is "twenty-one billion, two hundred thirty-three million, one hundred thousand, twenty-one".