21963312 has 140 divisors (see below), whose sum is σ = 73187280. Its totient is φ = 6251904.

The previous prime is 21963287. The next prime is 21963313. The reversal of 21963312 is 21336912.

21963312 is a `hidden beast` number, since 2 + 19 + 633 + 12 = 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.

It is not an unprimeable number, because it can be changed into a prime (21963313) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 81514 + ... + 81782.

Almost surely, 2^21963312 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 21963312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36593640).

21963312 is an abundant number, since it is smaller than the sum of its proper divisors (51223968).

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

21963312 is an equidigital number, since it uses as much as digits as its factorization.

21963312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302 (or 281 counting only the distinct ones).

The product of its digits is 1944, while the sum is 27.

The square root of 21963312 is about 4686.5031740094. The cubic root of 21963312 is about 280.0480869792.

The spelling of 21963312 in words is "twenty-one million, nine hundred sixty-three thousand, three hundred twelve".