21037968 has 120 divisors (see below), whose sum is σ = 69870528. Its totient is φ = 6003072.

The previous prime is 21037967. The next prime is 21038009. The reversal of 21037968 is 86973012.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21037967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26830 + ... + 27602.

Almost surely, 2^21037968 is an apocalyptic number.

21037968 is a gapful number since it is divisible by the number (28) 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 21037968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34935264).

21037968 is an abundant number, since it is smaller than the sum of its proper divisors (48832560).

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

21037968 is an equidigital number, since it uses as much as digits as its factorization.

21037968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 803 (or 785 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 21037968 is about 4586.7164725978. The cubic root of 21037968 is about 276.0585886963.

The spelling of 21037968 in words is "twenty-one million, thirty-seven thousand, nine hundred sixty-eight".