81427998168 has 320 divisors, whose sum is σ = 256446432000. Its totient is φ = 23926129920.

The previous prime is 81427998149. The next prime is 81427998191. The reversal of 81427998168 is 86189972418.

It is a super-2 number, since 2×81427998168² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 45668205 + ... + 45669987.

It is an arithmetic number, because the mean of its divisors is an integer number (801395100).

Almost surely, 2^81427998168 is an apocalyptic number.

81427998168 is a gapful number since it is divisible by the number (88) 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 81427998168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128223216000).

81427998168 is an abundant number, since it is smaller than the sum of its proper divisors (175018433832).

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

81427998168 is a wasteful number, since it uses less digits than its factorization.

81427998168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2004 (or 1991 counting only the distinct ones).

The product of its digits is 13934592, while the sum is 63.

The spelling of 81427998168 in words is "eighty-one billion, four hundred twenty-seven million, nine hundred ninety-eight thousand, one hundred sixty-eight".