81673885008 has 100 divisors (see below), whose sum is σ = 236479049268. Its totient is φ = 27214133760.

The previous prime is 81673884997. The next prime is 81673885019. The reversal of 81673885008 is 80058837618.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81673884997) and next prime (81673885019).

It can be written as a sum of positive squares in 2 ways, for example, as 76401382464 + 5272502544 = 276408^2 + 72612^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3816418 + ... + 3837758.

Almost surely, 2^81673885008 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 81673885008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118239524634).

81673885008 is an abundant number, since it is smaller than the sum of its proper divisors (154805164260).

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

81673885008 is a wasteful number, since it uses less digits than its factorization.

81673885008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24314 (or 24299 counting only the distinct ones).

The product of its (nonzero) digits is 2580480, while the sum is 54.

The spelling of 81673885008 in words is "eighty-one billion, six hundred seventy-three million, eight hundred eighty-five thousand, eight".