81641567268 has 72 divisors (see below), whose sum is σ = 207735528000. Its totient is φ = 27034451136.

The previous prime is 81641567219. The next prime is 81641567321. The reversal of 81641567268 is 86276514618.

81641567268 is a `hidden beast` number, since 8 + 16 + 4 + 1 + 567 + 2 + 68 = 666.

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, 4712430 + ... + 4729722.

Almost surely, 2^81641567268 is an apocalyptic number.

It is an amenable number.

81641567268 is an abundant number, since it is smaller than the sum of its proper divisors (126093960732).

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

81641567268 is a wasteful number, since it uses less digits than its factorization.

81641567268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18161 (or 18156 counting only the distinct ones).

The product of its digits is 3870720, while the sum is 54.

The spelling of 81641567268 in words is "eighty-one billion, six hundred forty-one million, five hundred sixty-seven thousand, two hundred sixty-eight".