21033040 has 120 divisors (see below), whose sum is σ = 59246208. Its totient is φ = 6800640.

The previous prime is 21033011. The next prime is 21033053. The reversal of 21033040 is 4033012.

It is a zygodrome in base 4.

It is a self number, because there is not a number n which added to its sum of digits gives 21033040.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 296205 + ... + 296275.

Almost surely, 2^21033040 is an apocalyptic number.

21033040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21033040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29623104).

21033040 is an abundant number, since it is smaller than the sum of its proper divisors (38213168).

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

21033040 is a wasteful number, since it uses less digits than its factorization.

21033040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137 (or 108 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 21033040 is about 4586.1792376661. The cubic root of 21033040 is about 276.0370320681.

Adding to 21033040 its reverse (4033012), we get a palindrome (25066052).

The spelling of 21033040 in words is "twenty-one million, thirty-three thousand, forty".