81786440160 has 144 divisors (see below), whose sum is σ = 279276575760. Its totient is φ = 21795624960.

The previous prime is 81786440149. The next prime is 81786440231. The reversal of 81786440160 is 6104468718.

81786440160 is a `hidden beast` number, since 81 + 78 + 6 + 440 + 1 + 60 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

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, 2313820 + ... + 2348900.

It is an arithmetic number, because the mean of its divisors is an integer number (1939420665).

Almost surely, 2^81786440160 is an apocalyptic number.

81786440160 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81786440160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139638287880).

81786440160 is an abundant number, since it is smaller than the sum of its proper divisors (197490135600).

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

81786440160 is a wasteful number, since it uses less digits than its factorization.

81786440160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36721 (or 36710 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The spelling of 81786440160 in words is "eighty-one billion, seven hundred eighty-six million, four hundred forty thousand, one hundred sixty".