81708912 has 100 divisors (see below), whose sum is σ = 240274056. Its totient is φ = 26801280.

The previous prime is 81708883. The next prime is 81708917. The reversal of 81708912 is 21980718.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81708917) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 86362 + ... + 87302.

Almost surely, 2^81708912 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 81708912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120137028).

81708912 is an abundant number, since it is smaller than the sum of its proper divisors (158565144).

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

81708912 is a wasteful number, since it uses less digits than its factorization.

81708912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1028 (or 1013 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 81708912 is about 9039.2982028474. The cubic root of 81708912 is about 433.9334632932.

The spelling of 81708912 in words is "eighty-one million, seven hundred eight thousand, nine hundred twelve".