81855174996 has 576 divisors, whose sum is σ = 270516879360. Its totient is φ = 21129102720.

The previous prime is 81855174967. The next prime is 81855174997. The reversal of 81855174996 is 69947155818.

81855174996 is a `hidden beast` number, since 8 + 1 + 8 + 551 + 74 + 9 + 9 + 6 = 666.

It is a Smith number, since the sum of its digits (63) coincides with the sum of the digits of its prime factors.

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

Its product of digits (21772800) is a multiple of the sum of its prime factors (486).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81855174997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 228008665 + ... + 228009023.

It is an arithmetic number, because the mean of its divisors is an integer number (469647360).

Almost surely, 2^81855174996 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 81855174996, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135258439680).

81855174996 is an abundant number, since it is smaller than the sum of its proper divisors (188661704364).

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

81855174996 is a wasteful number, since it uses less digits than its factorization.

81855174996 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 486 (or 472 counting only the distinct ones).

The product of its digits is 21772800, while the sum is 63.

The spelling of 81855174996 in words is "eighty-one billion, eight hundred fifty-five million, one hundred seventy-four thousand, nine hundred ninety-six".