81155442340 has 24 divisors (see below), whose sum is σ = 194773061952. Its totient is φ = 27824723040.

The previous prime is 81155442223. The next prime is 81155442373. The reversal of 81155442340 is 4324455118.

It is a self number, because there is not a number n which added to its sum of digits gives 81155442340.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 289840726 + ... + 289841005.

It is an arithmetic number, because the mean of its divisors is an integer number (8115544248).

Almost surely, 2^81155442340 is an apocalyptic number.

It is an amenable number.

81155442340 is an abundant number, since it is smaller than the sum of its proper divisors (113617619612).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81155442340 is a wasteful number, since it uses less digits than its factorization.

81155442340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 579681747 (or 579681745 counting only the distinct ones).

The product of its (nonzero) digits is 76800, while the sum is 37.

Adding to 81155442340 its reverse (4324455118), we get a palindrome (85479897458).

The spelling of 81155442340 in words is "eighty-one billion, one hundred fifty-five million, four hundred forty-two thousand, three hundred forty".