81618325 has 12 divisors (see below), whose sum is σ = 104697540. Its totient is φ = 63042560.

The previous prime is 81618323. The next prime is 81618347. The reversal of 81618325 is 52381618.

It can be written as a sum of positive squares in 6 ways, for example, as 221841 + 81396484 = 471^2 + 9022^2 .

It is not a de Polignac number, because 81618325 - 2¹ = 81618323 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81618323) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 55564 + ... + 57013.

It is an arithmetic number, because the mean of its divisors is an integer number (8724795).

Almost surely, 2^81618325 is an apocalyptic number.

It is an amenable number.

81618325 is a deficient number, since it is larger than the sum of its proper divisors (23079215).

81618325 is a wasteful number, since it uses less digits than its factorization.

81618325 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112616 (or 112611 counting only the distinct ones).

The product of its digits is 11520, while the sum is 34.

The square root of 81618325 is about 9034.2860813680. The cubic root of 81618325 is about 433.7730431496.

The spelling of 81618325 in words is "eighty-one million, six hundred eighteen thousand, three hundred twenty-five".