21252433021 has 8 divisors (see below), whose sum is σ = 22210119360. Its totient is φ = 20297552352.

The previous prime is 21252433009. The next prime is 21252433039. The reversal of 21252433021 is 12033425212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21252433021 - 2³¹ = 19104949373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21252433121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 685920 + ... + 716233.

It is an arithmetic number, because the mean of its divisors is an integer number (2776264920).

Almost surely, 2^21252433021 is an apocalyptic number.

It is an amenable number.

21252433021 is a deficient number, since it is larger than the sum of its proper divisors (957686339).

21252433021 is a wasteful number, since it uses less digits than its factorization.

21252433021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1402835.

The product of its (nonzero) digits is 2880, while the sum is 25.

Adding to 21252433021 its reverse (12033425212), we get a palindrome (33285858233).

The spelling of 21252433021 in words is "twenty-one billion, two hundred fifty-two million, four hundred thirty-three thousand, twenty-one".