21233616 has 20 divisors (see below), whose sum is σ = 54853632. Its totient is φ = 7077856.

The previous prime is 21233609. The next prime is 21233617. The reversal of 21233616 is 61633212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (24).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21233617) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 221136 + ... + 221231.

Almost surely, 2^21233616 is an apocalyptic number.

It is an amenable number.

21233616 is an abundant number, since it is smaller than the sum of its proper divisors (33620016).

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

21233616 is a wasteful number, since it uses less digits than its factorization.

21233616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442378 (or 442372 counting only the distinct ones).

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

The square root of 21233616 is about 4607.9947916637. The cubic root of 21233616 is about 276.9117088401.

Adding to 21233616 its reverse (61633212), we get a palindrome (82866828).

The spelling of 21233616 in words is "twenty-one million, two hundred thirty-three thousand, six hundred sixteen".