81044613 has 12 divisors (see below), whose sum is σ = 126069580. Its totient is φ = 49873536.

The previous prime is 81044597. The next prime is 81044629. The reversal of 81044613 is 31644018.

81044613 is a `hidden beast` number, since 8 + 1 + 0 + 44 + 613 = 666.

It is an interprime number because it is at equal distance from previous prime (81044597) and next prime (81044629).

It can be written as a sum of positive squares in 2 ways, for example, as 3305124 + 77739489 = 1818^2 + 8817^2 .

It is not a de Polignac number, because 81044613 - 2⁴ = 81044597 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81044653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 346228 + ... + 346461.

Almost surely, 2^81044613 is an apocalyptic number.

It is an amenable number.

81044613 is a deficient number, since it is larger than the sum of its proper divisors (45024967).

81044613 is a wasteful number, since it uses less digits than its factorization.

81044613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 692708 (or 692705 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 81044613 is about 9002.4781588183. The cubic root of 81044613 is about 432.7542924142.

The spelling of 81044613 in words is "eighty-one million, forty-four thousand, six hundred thirteen".