81878539176 has 128 divisors (see below), whose sum is σ = 260682624000. Its totient is φ = 23326301376.

The previous prime is 81878539123. The next prime is 81878539199. The reversal of 81878539176 is 67193587818.

81878539176 is a `hidden beast` number, since 8 + 1 + 87 + 8 + 539 + 17 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 446635 + ... + 602693.

It is an arithmetic number, because the mean of its divisors is an integer number (2036583000).

Almost surely, 2^81878539176 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81878539176, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130341312000).

81878539176 is an abundant number, since it is smaller than the sum of its proper divisors (178804084824).

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

81878539176 is a wasteful number, since it uses less digits than its factorization.

81878539176 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156428 (or 156418 counting only the distinct ones).

The product of its digits is 20321280, while the sum is 63.

The spelling of 81878539176 in words is "eighty-one billion, eight hundred seventy-eight million, five hundred thirty-nine thousand, one hundred seventy-six".