81718225 has 12 divisors (see below), whose sum is σ = 102845104. Its totient is φ = 64397520.

The previous prime is 81718211. The next prime is 81718229. The reversal of 81718225 is 52281718.

It is not a de Polignac number, because 81718225 - 2¹¹ = 81716177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81718229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22719 + ... + 26068.

Almost surely, 2^81718225 is an apocalyptic number.

It is an amenable number.

81718225 is a deficient number, since it is larger than the sum of its proper divisors (21126879).

81718225 is a wasteful number, since it uses less digits than its factorization.

81718225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48864 (or 48859 counting only the distinct ones).

The product of its digits is 8960, while the sum is 34.

The square root of 81718225 is about 9039.8133277187. The cubic root of 81718225 is about 433.9499489238.

The spelling of 81718225 in words is "eighty-one million, seven hundred eighteen thousand, two hundred twenty-five".