81655312 has 60 divisors (see below), whose sum is σ = 170267376. Its totient is φ = 37920960.

The previous prime is 81655289. The next prime is 81655349. The reversal of 81655312 is 21355618.

It is a super-3 number, since 3×81655312³ (a number of 25 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 386887 + ... + 387097.

Almost surely, 2^81655312 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 81655312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85133688).

81655312 is an abundant number, since it is smaller than the sum of its proper divisors (88612064).

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

81655312 is a wasteful number, since it uses less digits than its factorization.

81655312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324 (or 299 counting only the distinct ones).

The product of its digits is 7200, while the sum is 31.

The square root of 81655312 is about 9036.3328845279. The cubic root of 81655312 is about 433.8385576061.

The spelling of 81655312 in words is "eighty-one million, six hundred fifty-five thousand, three hundred twelve".