81673020 has 288 divisors, whose sum is σ = 308206080. Its totient is φ = 17210880.

The previous prime is 81673013. The next prime is 81673037. The reversal of 81673020 is 2037618.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 488977 + ... + 489143.

It is an arithmetic number, because the mean of its divisors is an integer number (1070160).

Almost surely, 2^81673020 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 81673020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (154103040).

81673020 is an abundant number, since it is smaller than the sum of its proper divisors (226533060).

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

81673020 is a wasteful number, since it uses less digits than its factorization.

81673020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225 (or 220 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 81673020 is about 9037.3126536598. The cubic root of 81673020 is about 433.8699164881.

The spelling of 81673020 in words is "eighty-one million, six hundred seventy-three thousand, twenty".