81678780054 has 64 divisors (see below), whose sum is σ = 185683819200. Its totient is φ = 26606797056.

The previous prime is 81678780013. The next prime is 81678780083. The reversal of 81678780054 is 45008787618.

It is a happy number.

It is a super-2 number, since 2×81678780054² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is a congruent number.

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, 334632 + ... + 524724.

It is an arithmetic number, because the mean of its divisors is an integer number (2901309675).

Almost surely, 2^81678780054 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81678780054, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92841909600).

81678780054 is an abundant number, since it is smaller than the sum of its proper divisors (104005039146).

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

81678780054 is a wasteful number, since it uses less digits than its factorization.

81678780054 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190286 (or 190280 counting only the distinct ones).

The product of its (nonzero) digits is 3010560, while the sum is 54.

The spelling of 81678780054 in words is "eighty-one billion, six hundred seventy-eight million, seven hundred eighty thousand, fifty-four".