81397115541225 has 81 divisors (see below), whose sum is σ = 160252847997879. Its totient is φ = 39464546378400.

The previous prime is 81397115541199. The next prime is 81397115541253. The reversal of 81397115541225 is 52214551179318.

The square root of 81397115541225 is 9022035.

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

81397115541225 is a `hidden beast` number, since 8 + 1 + 3 + 9 + 71 + 1 + 5 + 541 + 2 + 25 = 666.

It can be written as a sum of positive squares in only one way, i.e., 29302961594841 + 52094153946384 = 5413221^2 + 7217628^2 .

It is not a de Polignac number, because 81397115541225 - 2⁵ = 81397115541193 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 1488608436 + ... + 1488663114.

Almost surely, 2^{81397115541225} is an apocalyptic number.

81397115541225 is the 9022035-th square number.

81397115541225 is the 4511018-th centered octagonal number.

It is an amenable number.

81397115541225 is a deficient number, since it is larger than the sum of its proper divisors (78855732456654).

81397115541225 is an frugal number, since it uses more digits than its factorization.

81397115541225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109396 (or 54698 counting only the distinct ones).

The product of its digits is 3024000, while the sum is 54.

The spelling of 81397115541225 in words is "eighty-one trillion, three hundred ninety-seven billion, one hundred fifteen million, five hundred forty-one thousand, two hundred twenty-five".