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21068100 = 223652172

21068100 has 189 divisors, whose sum is σ = 72814567. Its totient is φ = 5287680.

The previous prime is 21068087. The next prime is 21068101. The reversal of 21068100 is 186012.

The square root of 21068100 is 4590.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 492804 + 20575296 = 702^2 + 4536^2 .

It is a super-2 number, since 2×210681002 = 887729675220000, which contains 22 as substring.

It is a hoax number, since the sum of its digits (18) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21068101) by changing a digit.

It is a polite number, since it can be written in 62 ways as a sum of consecutive naturals, for example, 1239292 + ... + 1239308.

It is a vampire number, since it can be written as 26018100 (with its own digits).

Almost surely, 221068100 is an apocalyptic number.

21068100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21068100 is the 4590-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21068100

21068100 is an abundant number, since it is smaller than the sum of its proper divisors (51746467).

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

21068100 is a wasteful number, since it uses less digits than its factorization.

21068100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66 (or 27 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The cubic root of 21068100 is about 276.1903224147.

The spelling of 21068100 in words is "twenty-one million, sixty-eight thousand, one hundred".