21633612 has 96 divisors (see below), whose sum is σ = 67812864. Its totient is φ = 5184000.

The previous prime is 21633611. The next prime is 21633617.

It is a happy number.

21633612 is nontrivially palindromic in base 10.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21633611) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11112 + ... + 12912.

It is an arithmetic number, because the mean of its divisors is an integer number (706384).

Almost surely, 2^21633612 is an apocalyptic number.

21633612 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21633612, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33906432).

21633612 is an abundant number, since it is smaller than the sum of its proper divisors (46179252).

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

21633612 is a wasteful number, since it uses less digits than its factorization.

21633612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1839 (or 1837 counting only the distinct ones).

The product of its digits is 1296, while the sum is 24.

The square root of 21633612 is about 4651.1946852395. The cubic root of 21633612 is about 278.6397117105.

It can be divided in two parts, 2163 and 3612, that added together give a palindrome (5775).

The spelling of 21633612 in words is "twenty-one million, six hundred thirty-three thousand, six hundred twelve".