21033630 has 48 divisors (see below), whose sum is σ = 55242720. Its totient is φ = 5552064.

The previous prime is 21033601. The next prime is 21033631. The reversal of 21033630 is 3633012.

It is a happy number.

21033630 is a `hidden beast` number, since 2 + 1 + 0 + 33 + 630 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21033631) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8136 + ... + 10404.

It is an arithmetic number, because the mean of its divisors is an integer number (1150890).

Almost surely, 2^21033630 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21033630, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27621360).

21033630 is an abundant number, since it is smaller than the sum of its proper divisors (34209090).

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

21033630 is a wasteful number, since it uses less digits than its factorization.

21033630 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2385 (or 2382 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 18.

The square root of 21033630 is about 4586.2435609113. The cubic root of 21033630 is about 276.0396130918.

Adding to 21033630 its reverse (3633012), we get a palindrome (24666642).

The spelling of 21033630 in words is "twenty-one million, thirty-three thousand, six hundred thirty".