81645578450 has 48 divisors (see below), whose sum is σ = 154426500000. Its totient is φ = 32110573440.

The previous prime is 81645578437. The next prime is 81645578477. The reversal of 81645578450 is 5487554618.

It is a junction number, because it is equal to n+sod(n) for n = 81645578392 and 81645578401.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 745301 + ... + 847799.

It is an arithmetic number, because the mean of its divisors is an integer number (3217218750).

Almost surely, 2^81645578450 is an apocalyptic number.

81645578450 is a deficient number, since it is larger than the sum of its proper divisors (72780921550).

81645578450 is a wasteful number, since it uses less digits than its factorization.

81645578450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102779 (or 102774 counting only the distinct ones).

The product of its (nonzero) digits is 5376000, while the sum is 53.

The spelling of 81645578450 in words is "eighty-one billion, six hundred forty-five million, five hundred seventy-eight thousand, four hundred fifty".