81328005604 has 12 divisors (see below), whose sum is σ = 142390624684. Its totient is φ = 40644969984.

The previous prime is 81328005569. The next prime is 81328005611. The reversal of 81328005604 is 40650082318.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 8510062500 + 72817943104 = 92250^2 + 269848^2 .

It is a super-2 number, since 2×81328005604² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4748589 + ... + 4765684.

Almost surely, 2^81328005604 is an apocalyptic number.

It is an amenable number.

81328005604 is a deficient number, since it is larger than the sum of its proper divisors (61062619080).

81328005604 is a wasteful number, since it uses less digits than its factorization.

81328005604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9516414 (or 9516412 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 37.

The spelling of 81328005604 in words is "eighty-one billion, three hundred twenty-eight million, five thousand, six hundred four".