81218508708 has 24 divisors (see below), whose sum is σ = 189518071680. Its totient is φ = 27071662240.

The previous prime is 81218508677. The next prime is 81218508713. The reversal of 81218508708 is 80780581218.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 168613 + ... + 436883.

It is an arithmetic number, because the mean of its divisors is an integer number (7896586320).

Almost surely, 2^81218508708 is an apocalyptic number.

It is an amenable number.

81218508708 is an abundant number, since it is smaller than the sum of its proper divisors (108299562972).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81218508708 is a wasteful number, since it uses less digits than its factorization.

81218508708 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293507 (or 293505 counting only the distinct ones).

The product of its (nonzero) digits is 286720, while the sum is 48.

The spelling of 81218508708 in words is "eighty-one billion, two hundred eighteen million, five hundred eight thousand, seven hundred eight".