66521 has 16 divisors (see below), whose sum is σ = 88704. Its totient is φ = 48384.
The previous prime is 66509. The next prime is 66523. The reversal of 66521 is 12566.
It is not a de Polignac number, because 66521 - 26 = 66457 is a prime.
It is a plaindrome in base 9.
It is a nialpdrome in base 10.
It is a zygodrome in base 9.
It is a junction number, because it is equal to n+sod(n) for n = 66493 and 66502.
It is not an unprimeable number, because it can be changed into a prime (66523) by changing a digit.
It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1526 + ... + 1568.
It is an arithmetic number, because the mean of its divisors is an integer number (5544).
266521 is an apocalyptic number.
It is an amenable number.
66521 is a deficient number, since it is larger than the sum of its proper divisors (22183).
66521 is a wasteful number, since it uses less digits than its factorization.
66521 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 80.
The product of its digits is 360, while the sum is 20.
The square root of 66521 is about 257.9166532041. The cubic root of 66521 is about 40.5184592985.
It can be divided in two parts, 665 and 21, that added together give a palindrome (686).
The spelling of 66521 in words is "sixty-six thousand, five hundred twenty-one".
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