21330736 has 40 divisors (see below), whose sum is σ = 47496960. Its totient is φ = 9090624.

The previous prime is 21330679. The next prime is 21330737. The reversal of 21330736 is 63703312.

It is a self number, because there is not a number n which added to its sum of digits gives 21330736.

It is not an unprimeable number, because it can be changed into a prime (21330737) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25005 + ... + 25843.

It is an arithmetic number, because the mean of its divisors is an integer number (1187424).

Almost surely, 2^21330736 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 21330736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23748480).

21330736 is an abundant number, since it is smaller than the sum of its proper divisors (26166224).

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

21330736 is a wasteful number, since it uses less digits than its factorization.

21330736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1081 (or 1075 counting only the distinct ones).

The product of its (nonzero) digits is 2268, while the sum is 25.

The square root of 21330736 is about 4618.5209753773. The cubic root of 21330736 is about 277.3332537187. Note that the first 3 decimals are identical.

The spelling of 21330736 in words is "twenty-one million, three hundred thirty thousand, seven hundred thirty-six".