81327226464 has 576 divisors, whose sum is σ = 273117132288. Its totient is φ = 22708224000.

The previous prime is 81327226457. The next prime is 81327226501. The reversal of 81327226464 is 46462272318.

It is a happy number.

81327226464 is a `hidden beast` number, since 8 + 1 + 327 + 2 + 264 + 64 = 666.

It is a super-2 number, since 2×81327226464² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

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 95 ways as a sum of consecutive naturals, for example, 316448224 + ... + 316448480.

It is an arithmetic number, because the mean of its divisors is an integer number (474161688).

Almost surely, 2^81327226464 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81327226464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136558566144).

81327226464 is an abundant number, since it is smaller than the sum of its proper divisors (191789905824).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81327226464 is a wasteful number, since it uses less digits than its factorization.

81327226464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451 (or 440 counting only the distinct ones).

The product of its digits is 774144, while the sum is 45.

The spelling of 81327226464 in words is "eighty-one billion, three hundred twenty-seven million, two hundred twenty-six thousand, four hundred sixty-four".