25621 has 2 divisors, whose sum is σ = 25622. Its totient is φ = 25620.
The previous prime is 25609. The next prime is 25633. The reversal of 25621 is 12652.
It is a happy number.
It is a balanced prime because it is at equal distance from previous prime (25609) and next prime (25633).
It can be written as a sum of positive squares in only one way, i.e., 18225 + 7396 = 135^2 + 86^2 .
It is a cyclic number.
It is not a de Polignac number, because 25621 - 25 = 25589 is a prime.
It is an Ulam number.
25621 is a lucky number.
It is a junction number, because it is equal to n+sod(n) for n = 25595 and 25604.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (25601) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12810 + 12811.
It is an arithmetic number, because the mean of its divisors is an integer number (12811).
225621 is an apocalyptic number.
It is an amenable number.
25621 is a deficient number, since it is larger than the sum of its proper divisors (1).
25621 is an equidigital number, since it uses as much as digits as its factorization.
25621 is an evil number, because the sum of its binary digits is even.
The product of its digits is 120, while the sum is 16.
The square root of 25621 is about 160.0656115473. The cubic root of 25621 is about 29.4803086054.
It can be divided in two parts, 25 and 621, that added together give a palindrome (646).
The spelling of 25621 in words is "twenty-five thousand, six hundred twenty-one".
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