81273405312 has 384 divisors, whose sum is σ = 277250688000. Its totient is φ = 22577356800.

The previous prime is 81273405289. The next prime is 81273405319. The reversal of 81273405312 is 21350437218.

81273405312 is a `hidden beast` number, since 8 + 12 + 73 + 40 + 531 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a super-2 number, since 2×81273405312² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81273405319) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7458364 + ... + 7469252.

It is an arithmetic number, because the mean of its divisors is an integer number (722007000).

Almost surely, 2^81273405312 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 81273405312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138625344000).

81273405312 is an abundant number, since it is smaller than the sum of its proper divisors (195977282688).

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

81273405312 is a wasteful number, since it uses less digits than its factorization.

81273405312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10970 (or 10955 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The spelling of 81273405312 in words is "eighty-one billion, two hundred seventy-three million, four hundred five thousand, three hundred twelve".