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21110213 = 73289181

21110213 has 4 divisors (see below), whose sum is σ = 21399468. Its totient is φ = 20820960.

The previous prime is 21110189. The next prime is 21110227. The reversal of 21110213 is 31201112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15737089 + 5373124 = 3967^2 + 2318^2 .

It is a cyclic number.

It is not a de Polignac number, because 21110213 - 26 = 21110149 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21110194 and 21110203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 144518 + ... + 144663.

It is an arithmetic number, because the mean of its divisors is an integer number (5349867).

Almost surely, 221110213 is an apocalyptic number.

It is an amenable number.

21110213 is a deficient number, since it is larger than the sum of its proper divisors (289255).

21110213 is an equidigital number, since it uses as much as digits as its factorization.

21110213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 289254.

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 21110213 is about 4594.5851825818. The cubic root of 21110213 is about 276.3742254367.

Adding to 21110213 its reverse (31201112), we get a palindrome (52311325).

The spelling of 21110213 in words is "twenty-one million, one hundred ten thousand, two hundred thirteen".

Divisors: 1 73 289181 21110213