81625 has 8 divisors (see below), whose sum is σ = 102024. Its totient is φ = 65200.

The previous prime is 81619. The next prime is 81629. The reversal of 81625 is 52618.

It is a happy number.

81625 is nontrivially palindromic in base 11.

It can be written as a sum of positive squares in 4 ways, for example, as 9801 + 71824 = 99^2 + 268^2 .

It is not a de Polignac number, because 81625 - 2¹³ = 73433 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81596 and 81605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 202 + ... + 451.

It is an arithmetic number, because the mean of its divisors is an integer number (12753).

2⁸¹⁶²⁵ is an apocalyptic number.

It is an amenable number.

81625 is a deficient number, since it is larger than the sum of its proper divisors (20399).

81625 is an equidigital number, since it uses as much as digits as its factorization.

81625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 668 (or 658 counting only the distinct ones).

The product of its digits is 480, while the sum is 22.

The square root of 81625 is about 285.7008925432. The cubic root of 81625 is about 43.3784867929.

It can be divided in two parts, 816 and 25, that added together give a square (841 = 29²).

The spelling of 81625 in words is "eighty-one thousand, six hundred twenty-five".