25580021 has 2 divisors, whose sum is σ = 25580022. Its totient is φ = 25580020.
The previous prime is 25579999. The next prime is 25580033. The reversal of 25580021 is 12008552.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 20151121 + 5428900 = 4489^2 + 2330^2 .
It is a cyclic number.
It is not a de Polignac number, because 25580021 - 222 = 21385717 is a prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (25580081) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (13) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12790010 + 12790011.
It is an arithmetic number, because the mean of its divisors is an integer number (12790011).
Almost surely, 225580021 is an apocalyptic number.
It is an amenable number.
25580021 is a deficient number, since it is larger than the sum of its proper divisors (1).
25580021 is an equidigital number, since it uses as much as digits as its factorization.
25580021 is an odious number, because the sum of its binary digits is odd.
The product of its (nonzero) digits is 800, while the sum is 23.
The square root of 25580021 is about 5057.6695226161. The cubic root of 25580021 is about 294.6458298693.
Adding to 25580021 its reverse (12008552), we get a palindrome (37588573).
The spelling of 25580021 in words is "twenty-five million, five hundred eighty thousand, twenty-one".
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