21172332 has 24 divisors (see below), whose sum is σ = 49613872. Its totient is φ = 7027200.

The previous prime is 21172331. The next prime is 21172337. The reversal of 21172332 is 23327112.

It is a junction number, because it is equal to n+sod(n) for n = 21172299 and 21172308.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21172331) 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, 769 + ... + 6552.

It is a self-describing number.

Almost surely, 2^21172332 is an apocalyptic number.

It is an amenable number.

21172332 is an abundant number, since it is smaller than the sum of its proper divisors (28441540).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21172332 is a wasteful number, since it uses less digits than its factorization.

21172332 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7569 (or 7567 counting only the distinct ones).

The product of its digits is 504, while the sum is 21.

The square root of 21172332 is about 4601.3402395389. The cubic root of 21172332 is about 276.6450466162.

Adding to 21172332 its reverse (23327112), we get a palindrome (44499444).

The spelling of 21172332 in words is "twenty-one million, one hundred seventy-two thousand, three hundred thirty-two".