81138791473272 has 128 divisors (see below), whose sum is σ = 242726464512000. Its totient is φ = 24965413349760.

The previous prime is 81138791473253. The next prime is 81138791473273. The reversal of 81138791473272 is 27237419783118.

81138791473272 is a `hidden beast` number, since 8 + 1 + 1 + 3 + 8 + 7 + 91 + 473 + 2 + 72 = 666.

81138791473272 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81138791473273) 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, 236911129 + ... + 237253367.

It is an arithmetic number, because the mean of its divisors is an integer number (1896300504000).

Almost surely, 2^{81138791473272} is an apocalyptic number.

It is an amenable number.

81138791473272 is an abundant number, since it is smaller than the sum of its proper divisors (161587673038728).

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

81138791473272 is a wasteful number, since it uses less digits than its factorization.

81138791473272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 426698 (or 426688 counting only the distinct ones).

The product of its digits is 28449792, while the sum is 63.

The spelling of 81138791473272 in words is "eighty-one trillion, one hundred thirty-eight billion, seven hundred ninety-one million, four hundred seventy-three thousand, two hundred seventy-two".