21033648 has 80 divisors (see below), whose sum is σ = 60933600. Its totient is φ = 6946560.

The previous prime is 21033647. The next prime is 21033659. The reversal of 21033648 is 84633012.

It is a happy number.

21033648 is a `hidden beast` number, since 2 + 10 + 3 + 3 + 648 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21033647) 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, 78058 + ... + 78326.

It is an arithmetic number, because the mean of its divisors is an integer number (761670).

Almost surely, 2^21033648 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 21033648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30466800).

21033648 is an abundant number, since it is smaller than the sum of its proper divisors (39899952).

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

21033648 is a wasteful number, since it uses less digits than its factorization.

21033648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 467 (or 455 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 21033648 is about 4586.2455233012. The cubic root of 21033648 is about 276.0396918341.

The spelling of 21033648 in words is "twenty-one million, thirty-three thousand, six hundred forty-eight".