21373632 has 280 divisors, whose sum is σ = 78679040. Its totient is φ = 5598720.

The previous prime is 21373591. The next prime is 21373657. The reversal of 21373632 is 23637312.

21373632 is a `hidden beast` number, since 21 + 3 + 7 + 3 + 632 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

Its product of digits (4536) is a multiple of the sum of its prime factors (81).

It is a junction number, because it is equal to n+sod(n) for n = 21373596 and 21373605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 689457 + ... + 689487.

Almost surely, 2^21373632 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 21373632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39339520).

21373632 is an abundant number, since it is smaller than the sum of its proper divisors (57305408).

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

21373632 is a wasteful number, since it uses less digits than its factorization.

21373632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81 (or 62 counting only the distinct ones).

The product of its digits is 4536, while the sum is 27.

The square root of 21373632 is about 4623.1625539235. The cubic root of 21373632 is about 277.5190344869.

The spelling of 21373632 in words is "twenty-one million, three hundred seventy-three thousand, six hundred thirty-two".