81449344636 has 48 divisors (see below), whose sum is σ = 156145893120. Its totient is φ = 36867600000.

The previous prime is 81449344601. The next prime is 81449344637. The reversal of 81449344636 is 63644394418.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81449344637) 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, 11076361 + ... + 11083711.

It is an arithmetic number, because the mean of its divisors is an integer number (3253039440).

Almost surely, 2^81449344636 is an apocalyptic number.

It is an amenable number.

81449344636 is a deficient number, since it is larger than the sum of its proper divisors (74696548484).

81449344636 is a wasteful number, since it uses less digits than its factorization.

81449344636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8386 (or 8384 counting only the distinct ones).

The product of its digits is 5971968, while the sum is 52.

The spelling of 81449344636 in words is "eighty-one billion, four hundred forty-nine million, three hundred forty-four thousand, six hundred thirty-six".