81444598225 has 9 divisors (see below), whose sum is σ = 100993071217. Its totient is φ = 65154537040.

The previous prime is 81444598057. The next prime is 81444598237. The reversal of 81444598225 is 52289544418.

The square root of 81444598225 is 285385.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 13461336529 + 67983261696 = 116023^2 + 260736^2 .

It is not a de Polignac number, because 81444598225 - 2²¹ = 81442501073 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1398387 + ... + 1455463.

Almost surely, 2^81444598225 is an apocalyptic number.

81444598225 is the 285385-th square number.

81444598225 is the 142693-rd centered octagonal number.

It is an amenable number.

81444598225 is a deficient number, since it is larger than the sum of its proper divisors (19548472992).

81444598225 is an frugal number, since it uses more digits than its factorization.

81444598225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114164 (or 57082 counting only the distinct ones).

The product of its digits is 3686400, while the sum is 52.

The spelling of 81444598225 in words is "eighty-one billion, four hundred forty-four million, five hundred ninety-eight thousand, two hundred twenty-five".