21233042021 has 2 divisors, whose sum is σ = 21233042022. Its totient is φ = 21233042020.

The previous prime is 21233042003. The next prime is 21233042023. The reversal of 21233042021 is 12024033212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19123017796 + 2110024225 = 138286^2 + 45935^2 .

It is a cyclic number.

It is not a de Polignac number, because 21233042021 - 2¹⁴ = 21233025637 is a prime.

Together with 21233042023, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21233041984 and 21233042002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21233042023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10616521010 + 10616521011.

It is an arithmetic number, because the mean of its divisors is an integer number (10616521011).

Almost surely, 2^21233042021 is an apocalyptic number.

It is an amenable number.

21233042021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21233042021 is an equidigital number, since it uses as much as digits as its factorization.

21233042021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 20.

Adding to 21233042021 its reverse (12024033212), we get a palindrome (33257075233).

The spelling of 21233042021 in words is "twenty-one billion, two hundred thirty-three million, forty-two thousand, twenty-one".