81583398138 has 16 divisors (see below), whose sum is σ = 178000141536. Its totient is φ = 24722241840.

The previous prime is 81583398137. The next prime is 81583398163. The reversal of 81583398138 is 83189338518.

It is a happy number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81583398137) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 618055981 + ... + 618056112.

It is an arithmetic number, because the mean of its divisors is an integer number (11125008846).

Almost surely, 2^81583398138 is an apocalyptic number.

81583398138 is an abundant number, since it is smaller than the sum of its proper divisors (96416743398).

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

81583398138 is a wasteful number, since it uses less digits than its factorization.

81583398138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1236112109.

The product of its digits is 4976640, while the sum is 57.

The spelling of 81583398138 in words is "eighty-one billion, five hundred eighty-three million, three hundred ninety-eight thousand, one hundred thirty-eight".