81911119237 has 16 divisors (see below), whose sum is σ = 86795804160. Its totient is φ = 77173786368.

The previous prime is 81911119231. The next prime is 81911119247. The reversal of 81911119237 is 73291111918.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 81911119237 - 2⁷ = 81911119109 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81911119193 and 81911119202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81911119231) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 370168 + ... + 548494.

It is an arithmetic number, because the mean of its divisors is an integer number (5424737760).

Almost surely, 2^81911119237 is an apocalyptic number.

It is an amenable number.

81911119237 is a deficient number, since it is larger than the sum of its proper divisors (4884684923).

81911119237 is a wasteful number, since it uses less digits than its factorization.

81911119237 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178740.

The product of its digits is 27216, while the sum is 43.

The spelling of 81911119237 in words is "eighty-one billion, nine hundred eleven million, one hundred nineteen thousand, two hundred thirty-seven".