81634355712 has 800 divisors, whose sum is σ = 304335854592. Its totient is φ = 21212430336.

The previous prime is 81634355711. The next prime is 81634355729. The reversal of 81634355712 is 21755343618.

It is a happy number.

81634355712 is a `hidden beast` number, since 8 + 1 + 634 + 3 + 5 + 5 + 7 + 1 + 2 = 666.

It is not an unprimeable number, because it can be changed into a prime (81634355711) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 366073233 + ... + 366073455.

Almost surely, 2^81634355712 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 81634355712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (152167927296).

81634355712 is an abundant number, since it is smaller than the sum of its proper divisors (222701498880).

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

81634355712 is a wasteful number, since it uses less digits than its factorization.

81634355712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 370 (or 345 counting only the distinct ones).

The product of its digits is 604800, while the sum is 45.

The spelling of 81634355712 in words is "eighty-one billion, six hundred thirty-four million, three hundred fifty-five thousand, seven hundred twelve".