81218459788 has 6 divisors (see below), whose sum is σ = 142132304636. Its totient is φ = 40609229892.

The previous prime is 81218459779. The next prime is 81218459789. The reversal of 81218459788 is 88795481218.

It is not an unprimeable number, because it can be changed into a prime (81218459789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10152307470 + ... + 10152307477.

Almost surely, 2^81218459788 is an apocalyptic number.

It is an amenable number.

81218459788 is a deficient number, since it is larger than the sum of its proper divisors (60913844848).

81218459788 is a wasteful number, since it uses less digits than its factorization.

81218459788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20304614951 (or 20304614949 counting only the distinct ones).

The product of its digits is 10321920, while the sum is 61.

The spelling of 81218459788 in words is "eighty-one billion, two hundred eighteen million, four hundred fifty-nine thousand, seven hundred eighty-eight".