81645438148 has 12 divisors (see below), whose sum is σ = 142881561900. Its totient is φ = 40822134752.

The previous prime is 81645438139. The next prime is 81645438163. The reversal of 81645438148 is 84183454618.

It can be written as a sum of positive squares in 2 ways, for example, as 60163259524 + 21482178624 = 245282^2 + 146568^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81645438095 and 81645438104.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 374178 + ... + 550726.

It is an arithmetic number, because the mean of its divisors is an integer number (11906796825).

Almost surely, 2^81645438148 is an apocalyptic number.

It is an amenable number.

81645438148 is a deficient number, since it is larger than the sum of its proper divisors (61236123752).

81645438148 is a wasteful number, since it uses less digits than its factorization.

81645438148 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292166 (or 292164 counting only the distinct ones).

The product of its digits is 2949120, while the sum is 52.

The spelling of 81645438148 in words is "eighty-one billion, six hundred forty-five million, four hundred thirty-eight thousand, one hundred forty-eight".