81135478380 has 96 divisors (see below), whose sum is σ = 248375232000. Its totient is φ = 19626094080.

The previous prime is 81135478367. The next prime is 81135478381. The reversal of 81135478380 is 8387453118.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (81135478381) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 167121 + ... + 436119.

It is an arithmetic number, because the mean of its divisors is an integer number (2587242000).

Almost surely, 2^81135478380 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 81135478380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (124187616000).

81135478380 is an abundant number, since it is smaller than the sum of its proper divisors (167239753620).

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

81135478380 is a wasteful number, since it uses less digits than its factorization.

81135478380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269479 (or 269477 counting only the distinct ones).

The product of its (nonzero) digits is 645120, while the sum is 48.

The spelling of 81135478380 in words is "eighty-one billion, one hundred thirty-five million, four hundred seventy-eight thousand, three hundred eighty".