21493632 has 64 divisors (see below), whose sum is σ = 57576960. Its totient is φ = 7104000.

The previous prime is 21493621. The next prime is 21493639. The reversal of 21493632 is 23639412.

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 21493632.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21493639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85507 + ... + 85757.

It is an arithmetic number, because the mean of its divisors is an integer number (899640).

Almost surely, 2^21493632 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 21493632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28788480).

21493632 is an abundant number, since it is smaller than the sum of its proper divisors (36083328).

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

21493632 is a wasteful number, since it uses less digits than its factorization.

21493632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 491 (or 479 counting only the distinct ones).

The product of its digits is 7776, while the sum is 30.

The square root of 21493632 is about 4636.1225177944. The cubic root of 21493632 is about 278.0374326352.

The spelling of 21493632 in words is "twenty-one million, four hundred ninety-three thousand, six hundred thirty-two".