81265805712 has 720 divisors, whose sum is σ = 298491228672. Its totient is φ = 20860830720.

The previous prime is 81265805689. The next prime is 81265805771. The reversal of 81265805712 is 21750856218.

81265805712 is a `hidden beast` number, since 8 + 1 + 2 + 6 + 580 + 57 + 12 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 448982262 + ... + 448982442.

Almost surely, 2^81265805712 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 81265805712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (149245614336).

81265805712 is an abundant number, since it is smaller than the sum of its proper divisors (217225422960).

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

81265805712 is a wasteful number, since it uses less digits than its factorization.

81265805712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280 (or 253 counting only the distinct ones).

The product of its (nonzero) digits is 268800, while the sum is 45.

The spelling of 81265805712 in words is "eighty-one billion, two hundred sixty-five million, eight hundred five thousand, seven hundred twelve".