81583935641 has 16 divisors (see below), whose sum is σ = 88585059024. Its totient is φ = 74688870144.

The previous prime is 81583935619. The next prime is 81583935701. The reversal of 81583935641 is 14653938518.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 4579905625 + 77004030016 = 67675^2 + 277496^2 .

It is a cyclic number.

It is not a de Polignac number, because 81583935641 - 2⁶ = 81583935577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81583935241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 761591 + ... + 862083.

It is an arithmetic number, because the mean of its divisors is an integer number (5536566189).

Almost surely, 2^81583935641 is an apocalyptic number.

It is an amenable number.

81583935641 is a deficient number, since it is larger than the sum of its proper divisors (7001123383).

81583935641 is a wasteful number, since it uses less digits than its factorization.

81583935641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101020.

The product of its digits is 3110400, while the sum is 53.

The spelling of 81583935641 in words is "eighty-one billion, five hundred eighty-three million, nine hundred thirty-five thousand, six hundred forty-one".