81781775376 has 80 divisors (see below), whose sum is σ = 246378576000. Its totient is φ = 23366216832.

The previous prime is 81781775359. The next prime is 81781775419. The reversal of 81781775376 is 67357718718.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2467191 + ... + 2500118.

It is an arithmetic number, because the mean of its divisors is an integer number (3079732200).

Almost surely, 2^81781775376 is an apocalyptic number.

It is an amenable number.

81781775376 is an abundant number, since it is smaller than the sum of its proper divisors (164596800624).

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

81781775376 is a wasteful number, since it uses less digits than its factorization.

81781775376 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4967341 (or 4967321 counting only the distinct ones).

The product of its digits is 13829760, while the sum is 60.

The spelling of 81781775376 in words is "eighty-one billion, seven hundred eighty-one million, seven hundred seventy-five thousand, three hundred seventy-six".