21303912 has 64 divisors (see below), whose sum is σ = 61303680. Its totient is φ = 6043392.

The previous prime is 21303901. The next prime is 21303917. The reversal of 21303912 is 21930312.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21303917) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28698 + ... + 29430.

It is an arithmetic number, because the mean of its divisors is an integer number (957870).

Almost surely, 2^21303912 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 21303912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30651840).

21303912 is an abundant number, since it is smaller than the sum of its proper divisors (39999768).

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

21303912 is a wasteful number, since it uses less digits than its factorization.

21303912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 922 (or 918 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 21.

The square root of 21303912 is about 4615.6161018872. The cubic root of 21303912 is about 277.2169535013.

The spelling of 21303912 in words is "twenty-one million, three hundred three thousand, nine hundred twelve".