81466419515625 has 315 divisors, whose sum is σ = 155669184342529. Its totient is φ = 42457716000000.

The previous prime is 81466419515597. The next prime is 81466419515641. The reversal of 81466419515625 is 52651591466418.

It is a happy number.

The square root of 81466419515625 is 9025875.

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

81466419515625 is a `hidden beast` number, since 8 + 1 + 4 + 6 + 6 + 4 + 19 + 51 + 562 + 5 = 666.

It can be written as a sum of positive squares in 10 ways, for example, as 18236632170969 + 63229787344656 = 4270437^2 + 7951716^2 .

It is not a de Polignac number, because 81466419515625 - 2³⁷ = 81328980562153 is a prime.

It is a Duffinian number.

Its product of digits (62208000) is a multiple of the sum of its prime divisors (192).

It is an unprimeable number.

It is a polite number, since it can be written in 314 ways as a sum of consecutive naturals, for example, 720941765569 + ... + 720941765681.

Almost surely, 2^{81466419515625} is an apocalyptic number.

81466419515625 is the 9025875-th square number.

81466419515625 is the 4512938-th centered octagonal number.

It is an amenable number.

81466419515625 is a deficient number, since it is larger than the sum of its proper divisors (74202764826904).

81466419515625 is an frugal number, since it uses more digits than its factorization.

81466419515625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410 (or 192 counting only the distinct ones).

The product of its digits is 62208000, while the sum is 63.

The spelling of 81466419515625 in words is "eighty-one trillion, four hundred sixty-six billion, four hundred nineteen million, five hundred fifteen thousand, six hundred twenty-five".