81106613 has 6 divisors (see below), whose sum is σ = 94348566. Its totient is φ = 69519912.

The previous prime is 81106607. The next prime is 81106621. The reversal of 81106613 is 31660118.

It can be written as a sum of positive squares in only one way, i.e., 74252689 + 6853924 = 8617^2 + 2618^2 .

It is not a de Polignac number, because 81106613 - 2⁶ = 81106549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81126613) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 827570 + ... + 827667.

It is an arithmetic number, because the mean of its divisors is an integer number (15724761).

Almost surely, 2^81106613 is an apocalyptic number.

It is an amenable number.

81106613 is a deficient number, since it is larger than the sum of its proper divisors (13241953).

81106613 is a wasteful number, since it uses less digits than its factorization.

81106613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1655251 (or 1655244 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 81106613 is about 9005.9209967665. The cubic root of 81106613 is about 432.8646181804.

The spelling of 81106613 in words is "eighty-one million, one hundred six thousand, six hundred thirteen".