221525 has 6 divisors (see below), whose sum is σ = 274722. Its totient is φ = 177200.

The previous prime is 221509. The next prime is 221537. The reversal of 221525 is 525122.

221525 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 68644 + 152881 = 262^2 + 391^2 .

It is not a de Polignac number, because 221525 - 2⁴ = 221509 is a prime.

It is a Duffinian number.

It is a plaindrome in base 9.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4406 + ... + 4455.

It is an arithmetic number, because the mean of its divisors is an integer number (45787).

2²²¹⁵²⁵ is an apocalyptic number.

221525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

221525 is a deficient number, since it is larger than the sum of its proper divisors (53197).

221525 is an equidigital number, since it uses as much as digits as its factorization.

221525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8871 (or 8866 counting only the distinct ones).

The product of its digits is 200, while the sum is 17.

The square root of 221525 is about 470.6644239795. The cubic root of 221525 is about 60.5072732189.

Adding to 221525 its reverse (525122), we get a palindrome (746647).

The spelling of 221525 in words is "two hundred twenty-one thousand, five hundred twenty-five".