21064000 has 56 divisors (see below), whose sum is σ = 52184808. Its totient is φ = 8422400.

The previous prime is 21063997. The next prime is 21064009. The reversal of 21064000 is 46012.

It can be written as a sum of positive squares in 4 ways, for example, as 3154176 + 17909824 = 1776^2 + 4232^2 .

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21064009) 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, 6684 + ... + 9316.

Almost surely, 2^21064000 is an apocalyptic number.

21064000 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 21064000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26092404).

21064000 is an abundant number, since it is smaller than the sum of its proper divisors (31120808).

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

21064000 is an equidigital number, since it uses as much as digits as its factorization.

21064000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2660 (or 2640 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21064000 is about 4589.5533551752. The cubic root of 21064000 is about 276.1724050611.

The spelling of 21064000 in words is "twenty-one million, sixty-four thousand".