• 640212 = 4098688441 is an anagram of the next square 640222 = 4098816484.
64021 has 4 divisors (see below), whose sum is σ = 64972. Its totient is φ = 63072.
The previous prime is 64019. The next prime is 64033. The reversal of 64021 is 12046.
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 45796 + 18225 = 214^2 + 135^2 .
It is not a de Polignac number, because 64021 - 21 = 64019 is a prime.
It is a Duffinian number.
64021 is a lucky number.
It is a nialpdrome in base 11.
It is a zygodrome in base 11.
It is a junction number, because it is equal to n+sod(n) for n = 63992 and 64010.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (64081) by changing a digit.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 366 + ... + 511.
It is an arithmetic number, because the mean of its divisors is an integer number (16243).
264021 is an apocalyptic number.
It is an amenable number.
64021 is a deficient number, since it is larger than the sum of its proper divisors (951).
64021 is an equidigital number, since it uses as much as digits as its factorization.
64021 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 950.
The product of its (nonzero) digits is 48, while the sum is 13.
The square root of 64021 is about 253.0237143036. The cubic root of 64021 is about 40.0043745216.
Adding to 64021 its reverse (12046), we get a palindrome (76067).
The spelling of 64021 in words is "sixty-four thousand, twenty-one".
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