81117106849 has 4 divisors (see below), whose sum is σ = 81165710740. Its totient is φ = 81068502960.

The previous prime is 81117106831. The next prime is 81117106883. The reversal of 81117106849 is 94860171118.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 62240270400 + 18876836449 = 249480^2 + 137393^2 .

It is a cyclic number.

It is not a de Polignac number, because 81117106849 - 2⁵ = 81117106817 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81117106799 and 81117106808.

It is not an unprimeable number, because it can be changed into a prime (81117106249) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24299442 + ... + 24302779.

It is an arithmetic number, because the mean of its divisors is an integer number (20291427685).

Almost surely, 2^81117106849 is an apocalyptic number.

It is an amenable number.

81117106849 is a deficient number, since it is larger than the sum of its proper divisors (48603891).

81117106849 is a wasteful number, since it uses less digits than its factorization.

81117106849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48603890.

The product of its (nonzero) digits is 96768, while the sum is 46.

The spelling of 81117106849 in words is "eighty-one billion, one hundred seventeen million, one hundred six thousand, eight hundred forty-nine".