81237161975 has 12 divisors (see below), whose sum is σ = 103076735256. Its totient is φ = 63478339680.

The previous prime is 81237161959. The next prime is 81237162007. The reversal of 81237161975 is 57916173218.

It is a happy number.

It is not a de Polignac number, because 81237161975 - 2⁴ = 81237161959 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 37783652 + ... + 37785801.

It is an arithmetic number, because the mean of its divisors is an integer number (8589727938).

Almost surely, 2^81237161975 is an apocalyptic number.

81237161975 is a deficient number, since it is larger than the sum of its proper divisors (21839573281).

81237161975 is a wasteful number, since it uses less digits than its factorization.

81237161975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75569506 (or 75569501 counting only the distinct ones).

The product of its digits is 635040, while the sum is 50.

The spelling of 81237161975 in words is "eighty-one billion, two hundred thirty-seven million, one hundred sixty-one thousand, nine hundred seventy-five".