1525 has 6 divisors (see below), whose sum is σ = 1922.
Its totient is φ = 1200.
The previous prime is 1523. The next prime is 1531. The reversal of 1525 is 5251.
1525 is nontrivially palindromic in base 4 and base 16.
It can be written as a sum of positive squares in 3 ways, for example, as 4 + 1521 = 2^2 + 39^2
It is not a de Polignac number, because 1525 - 21 = 1523 is a prime.
It is a Duffinian number.
1525 is an undulating number in base 16.
It is a plaindrome in base 11 and base 14.
It is a nialpdrome in base 5 and base 12.
It is a zygodrome in base 4.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (1523) by changing a digit.
It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6 + ... + 55.
21525 is an apocalyptic number.
1525 is the 25-th heptagonal number.
It is an amenable number.
1525 is a deficient number, since it is larger than the sum of its proper divisors (397).
1525 is an equidigital number, since it uses as much as digits as its factorization.
1525 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 71 (or 66 counting only the distinct ones).
The product of its digits is 50, while the sum is 13.
The square root of 1525 is about 39.0512483795.
The cubic root of 1525 is about 11.5103875898.
Adding to 1525 its reverse (5251), we get a palindrome (6776).
The spelling of 1525 in words is "one thousand, five hundred twenty-five".