81664148160 has 560 divisors, whose sum is σ = 342725898240. Its totient is φ = 18062714880.

The previous prime is 81664148141. The next prime is 81664148173. The reversal of 81664148160 is 6184146618.

81664148160 is a `hidden beast` number, since 8 + 166 + 4 + 1 + 481 + 6 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (560).

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

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, 5617381 + ... + 5631899.

Almost surely, 2^81664148160 is an apocalyptic number.

81664148160 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 81664148160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (171362949120).

81664148160 is an abundant number, since it is smaller than the sum of its proper divisors (261061750080).

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

81664148160 is a wasteful number, since it uses less digits than its factorization.

81664148160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14586 (or 14567 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 45.

The spelling of 81664148160 in words is "eighty-one billion, six hundred sixty-four million, one hundred forty-eight thousand, one hundred sixty".