81241225 has 12 divisors (see below), whose sum is σ = 108488716. Its totient is φ = 59993280.

The previous prime is 81241219. The next prime is 81241229. The reversal of 81241225 is 52214218.

It can be written as a sum of positive squares in 6 ways, for example, as 5968249 + 75272976 = 2443^2 + 8676^2 .

It is not a de Polignac number, because 81241225 - 2¹¹ = 81239177 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81241225.

It is not an unprimeable number, because it can be changed into a prime (81241229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 124662 + ... + 125311.

Almost surely, 2^81241225 is an apocalyptic number.

It is an amenable number.

81241225 is a deficient number, since it is larger than the sum of its proper divisors (27247491).

81241225 is a wasteful number, since it uses less digits than its factorization.

81241225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249996 (or 249991 counting only the distinct ones).

The product of its digits is 1280, while the sum is 25.

The square root of 81241225 is about 9013.3914260948. The cubic root of 81241225 is about 433.1039598052.

The spelling of 81241225 in words is "eighty-one million, two hundred forty-one thousand, two hundred twenty-five".