81998040608 has 48 divisors (see below), whose sum is σ = 176218900704. Its totient is φ = 37248668160.

The previous prime is 81998040547. The next prime is 81998040613. The reversal of 81998040608 is 80604089918.

It is a Cunningham number, because it is equal to 286353²-1.

It is a self number, because there is not a number n which added to its sum of digits gives 81998040608.

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, 501116 + ... + 644292.

It is an arithmetic number, because the mean of its divisors is an integer number (3671227098).

Almost surely, 2^81998040608 is an apocalyptic number.

81998040608 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

81998040608 is an abundant number, since it is smaller than the sum of its proper divisors (94220860096).

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

81998040608 is a wasteful number, since it uses less digits than its factorization.

81998040608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144825 (or 144817 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 53.

The spelling of 81998040608 in words is "eighty-one billion, nine hundred ninety-eight million, forty thousand, six hundred eight".