21191232 has 112 divisors (see below), whose sum is σ = 61000640. Its totient is φ = 6469632.

The previous prime is 21191201. The next prime is 21191239. The reversal of 21191232 is 23219112.

It is a junction number, because it is equal to n+sod(n) for n = 21191199 and 21191208.

It is not an unprimeable number, because it can be changed into a prime (21191239) 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, 134898 + ... + 135054.

Almost surely, 2^21191232 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21191232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30500320).

21191232 is an abundant number, since it is smaller than the sum of its proper divisors (39809408).

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

21191232 is a wasteful number, since it uses less digits than its factorization.

21191232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 228 (or 218 counting only the distinct ones).

The product of its digits is 216, while the sum is 21.

The square root of 21191232 is about 4603.3935308639. The cubic root of 21191232 is about 276.7273401230.

The spelling of 21191232 in words is "twenty-one million, one hundred ninety-one thousand, two hundred thirty-two".