81182321583 has 16 divisors (see below), whose sum is σ = 118142603136. Its totient is φ = 49176729440.

The previous prime is 81182321557. The next prime is 81182321599. The reversal of 81182321583 is 38512328118.

It is a cyclic number.

It is not a de Polignac number, because 81182321583 - 2²¹ = 81180224431 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81182325583) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 550041 + ... + 681842.

It is an arithmetic number, because the mean of its divisors is an integer number (7383912696).

Almost surely, 2^81182321583 is an apocalyptic number.

81182321583 is a deficient number, since it is larger than the sum of its proper divisors (36960281553).

81182321583 is a wasteful number, since it uses less digits than its factorization.

81182321583 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1233894.

The product of its digits is 92160, while the sum is 42.

The spelling of 81182321583 in words is "eighty-one billion, one hundred eighty-two million, three hundred twenty-one thousand, five hundred eighty-three".