81005811760 has 20 divisors (see below), whose sum is σ = 188338512528. Its totient is φ = 32402324672.

The previous prime is 81005811751. The next prime is 81005811769. The reversal of 81005811760 is 6711850018.

It is an interprime number because it is at equal distance from previous prime (81005811751) and next prime (81005811769).

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (81005811769) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 506286244 + ... + 506286403.

Almost surely, 2^81005811760 is an apocalyptic number.

81005811760 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81005811760 is an abundant number, since it is smaller than the sum of its proper divisors (107332700768).

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

81005811760 is a wasteful number, since it uses less digits than its factorization.

81005811760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1012572660 (or 1012572654 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 37.

The spelling of 81005811760 in words is "eighty-one billion, five million, eight hundred eleven thousand, seven hundred sixty".