81349691041 has 4 divisors (see below), whose sum is σ = 81708059952. Its totient is φ = 80991322132.

The previous prime is 81349691039. The next prime is 81349691113. The reversal of 81349691041 is 14019694318.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81349691041 - 2¹ = 81349691039 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81349690982 and 81349691000.

It is not an unprimeable number, because it can be changed into a prime (81349671041) 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 3 ways as a sum of consecutive naturals, for example, 179184115 + ... + 179184568.

It is an arithmetic number, because the mean of its divisors is an integer number (20427014988).

Almost surely, 2^81349691041 is an apocalyptic number.

It is an amenable number.

81349691041 is a deficient number, since it is larger than the sum of its proper divisors (358368911).

81349691041 is a wasteful number, since it uses less digits than its factorization.

81349691041 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358368910.

The product of its (nonzero) digits is 186624, while the sum is 46.

The spelling of 81349691041 in words is "eighty-one billion, three hundred forty-nine million, six hundred ninety-one thousand, forty-one".