81669168 has 160 divisors (see below), whose sum is σ = 271411200. Its totient is φ = 23030784.

The previous prime is 81669151. The next prime is 81669187. The reversal of 81669168 is 86196618.

It is a happy number.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 341593 + ... + 341831.

It is an arithmetic number, because the mean of its divisors is an integer number (1696320).

Almost surely, 2^81669168 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 81669168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135705600).

81669168 is an abundant number, since it is smaller than the sum of its proper divisors (189742032).

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

81669168 is a wasteful number, since it uses less digits than its factorization.

81669168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 376 (or 364 counting only the distinct ones).

The product of its digits is 124416, while the sum is 45.

The square root of 81669168 is about 9037.0995346959. The cubic root of 81669168 is about 433.8630954139.

The spelling of 81669168 in words is "eighty-one million, six hundred sixty-nine thousand, one hundred sixty-eight".