81571877760 has 64 divisors (see below), whose sum is σ = 260010366480. Its totient is φ = 21752500224.

The previous prime is 81571877729. The next prime is 81571877773. The reversal of 81571877760 is 6777817518.

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 81571877760.

It is a congruent number.

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, 21240757 + ... + 21244596.

Almost surely, 2^81571877760 is an apocalyptic number.

81571877760 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81571877760 is an abundant number, since it is smaller than the sum of its proper divisors (178438488720).

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

81571877760 is a wasteful number, since it uses less digits than its factorization.

81571877760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42485375 (or 42485363 counting only the distinct ones).

The product of its (nonzero) digits is 4609920, while the sum is 57.

The spelling of 81571877760 in words is "eighty-one billion, five hundred seventy-one million, eight hundred seventy-seven thousand, seven hundred sixty".