81425 has 6 divisors (see below), whose sum is σ = 100998. Its totient is φ = 65120.

The previous prime is 81421. The next prime is 81439. The reversal of 81425 is 52418.

It can be written as a sum of positive squares in 3 ways, for example, as 15376 + 66049 = 124^2 + 257^2 .

It is not a de Polignac number, because 81425 - 2² = 81421 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81397 and 81406.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 81425.

It is not an unprimeable number, because it can be changed into a prime (81421) 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, 1604 + ... + 1653.

It is an arithmetic number, because the mean of its divisors is an integer number (16833).

2⁸¹⁴²⁵ is an apocalyptic number.

It is an amenable number.

81425 is a deficient number, since it is larger than the sum of its proper divisors (19573).

81425 is a wasteful number, since it uses less digits than its factorization.

81425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3267 (or 3262 counting only the distinct ones).

The product of its digits is 320, while the sum is 20.

The square root of 81425 is about 285.3506614676. The cubic root of 81425 is about 43.3430287313.

The spelling of 81425 in words is "eighty-one thousand, four hundred twenty-five".