19810131641 has 4 divisors (see below), whose sum is σ = 19832618484. Its totient is φ = 19787644800.

The previous prime is 19810131613. The next prime is 19810131647. The reversal of 19810131641 is 14613101891.

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 6881532025 + 12928599616 = 82955^2 + 113704^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19810131641 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (19810131647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11242100 + ... + 11243861.

It is an arithmetic number, because the mean of its divisors is an integer number (4958154621).

Almost surely, 2^19810131641 is an apocalyptic number.

It is an amenable number.

19810131641 is a deficient number, since it is larger than the sum of its proper divisors (22486843).

19810131641 is an equidigital number, since it uses as much as digits as its factorization.

19810131641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22486842.

The product of its (nonzero) digits is 5184, while the sum is 35.

The spelling of 19810131641 in words is "nineteen billion, eight hundred ten million, one hundred thirty-one thousand, six hundred forty-one".