81275166720 has 1120 divisors, whose sum is σ = 339123381696. Its totient is φ = 18402508800.

The previous prime is 81275166691. The next prime is 81275166733. The reversal of 81275166720 is 2766157218.

81275166720 is a `hidden beast` number, since 8 + 127 + 516 + 6 + 7 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 620421055 + ... + 620421185.

Almost surely, 2^81275166720 is an apocalyptic number.

81275166720 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81275166720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (169561690848).

81275166720 is an abundant number, since it is smaller than the sum of its proper divisors (257848214976).

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

81275166720 is a wasteful number, since it uses less digits than its factorization.

81275166720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202 (or 169 counting only the distinct ones).

The product of its (nonzero) digits is 282240, while the sum is 45.

The spelling of 81275166720 in words is "eighty-one billion, two hundred seventy-five million, one hundred sixty-six thousand, seven hundred twenty".