81347274749 has 6 divisors (see below), whose sum is σ = 88086102426. Its totient is φ = 75089791920.

The previous prime is 81347274727. The next prime is 81347274763. The reversal of 81347274749 is 94747274318.

It can be written as a sum of positive squares in 3 ways, for example, as 2391894649 + 78955380100 = 48907^2 + 280990^2 .

It is not a de Polignac number, because 81347274749 - 2⁸ = 81347274493 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81347274694 and 81347274703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81347274049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 240672242 + ... + 240672579.

It is an arithmetic number, because the mean of its divisors is an integer number (14681017071).

Almost surely, 2^81347274749 is an apocalyptic number.

It is an amenable number.

81347274749 is a deficient number, since it is larger than the sum of its proper divisors (6738827677).

81347274749 is a wasteful number, since it uses less digits than its factorization.

81347274749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 481344847 (or 481344834 counting only the distinct ones).

The product of its digits is 9483264, while the sum is 56.

The spelling of 81347274749 in words is "eighty-one billion, three hundred forty-seven million, two hundred seventy-four thousand, seven hundred forty-nine".