21033312 has 24 divisors (see below), whose sum is σ = 55212696. Its totient is φ = 7011072.

The previous prime is 21033289. The next prime is 21033317. The reversal of 21033312 is 21333012.

It is a tau number, because it is divible by the number of its divisors (24).

It is a junction number, because it is equal to n+sod(n) for n = 21033291 and 21033300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21033317) 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, 109453 + ... + 109644.

It is an arithmetic number, because the mean of its divisors is an integer number (2300529).

Almost surely, 2^21033312 is an apocalyptic number.

It is an amenable number.

21033312 is an abundant number, since it is smaller than the sum of its proper divisors (34179384).

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

21033312 is a wasteful number, since it uses less digits than its factorization.

21033312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219110 (or 219102 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 15.

The square root of 21033312 is about 4586.2088918845. The cubic root of 21033312 is about 276.0382219698.

Adding to 21033312 its reverse (21333012), we get a palindrome (42366324).

The spelling of 21033312 in words is "twenty-one million, thirty-three thousand, three hundred twelve".