81644929348 has 24 divisors (see below), whose sum is σ = 143426588760. Its totient is φ = 40666022400.

The previous prime is 81644929343. The next prime is 81644929349. The reversal of 81644929348 is 84392944618.

It can be written as a sum of positive squares in 4 ways, for example, as 12411742464 + 69233186884 = 111408^2 + 263122^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81644929292 and 81644929301.

It is not an unprimeable number, because it can be changed into a prime (81644929343) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 3044398 + ... + 3071098.

It is an arithmetic number, because the mean of its divisors is an integer number (5976107865).

Almost surely, 2^81644929348 is an apocalyptic number.

It is an amenable number.

81644929348 is a deficient number, since it is larger than the sum of its proper divisors (61781659412).

81644929348 is a wasteful number, since it uses less digits than its factorization.

81644929348 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29607 (or 29605 counting only the distinct ones).

The product of its digits is 11943936, while the sum is 58.

The spelling of 81644929348 in words is "eighty-one billion, six hundred forty-four million, nine hundred twenty-nine thousand, three hundred forty-eight".