21036672 has 80 divisors (see below), whose sum is σ = 62635650. Its totient is φ = 7008768.

The previous prime is 21036671. The next prime is 21036689. The reversal of 21036672 is 27663012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 11451456 + 9585216 = 3384^2 + 3096^2 .

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

It is a zygodrome in base 4.

It is not an unprimeable number, because it can be changed into a prime (21036671) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 9354 + ... + 11382.

Almost surely, 2^21036672 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 21036672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31317825).

21036672 is an abundant number, since it is smaller than the sum of its proper divisors (41598978).

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

21036672 is an equidigital number, since it uses as much as digits as its factorization.

21036672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2055 (or 2034 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 27.

The square root of 21036672 is about 4586.5751928863. The cubic root of 21036672 is about 276.0529199093.

Adding to 21036672 its reverse (27663012), we get a palindrome (48699684).

The spelling of 21036672 in words is "twenty-one million, thirty-six thousand, six hundred seventy-two".