81138345345 has 24 divisors (see below), whose sum is σ = 140755456296. Its totient is φ = 43238197248.

The previous prime is 81138345257. The next prime is 81138345371. The reversal of 81138345345 is 54354383118.

It is a happy number.

81138345345 is a `hidden beast` number, since 8 + 113 + 83 + 453 + 4 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 26826508944 + 54311836401 = 163788^2 + 233049^2 .

It is not a de Polignac number, because 81138345345 - 2¹⁹ = 81137821057 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 81138345345.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 686022 + ... + 795551.

It is an arithmetic number, because the mean of its divisors is an integer number (5864810679).

Almost surely, 2^81138345345 is an apocalyptic number.

It is an amenable number.

81138345345 is a deficient number, since it is larger than the sum of its proper divisors (59617110951).

81138345345 is a wasteful number, since it uses less digits than its factorization.

81138345345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1482801 (or 1482798 counting only the distinct ones).

The product of its digits is 691200, while the sum is 45.

The spelling of 81138345345 in words is "eighty-one billion, one hundred thirty-eight million, three hundred forty-five thousand, three hundred forty-five".