81978112 has 36 divisors (see below), whose sum is σ = 165277840. Its totient is φ = 40578048.

The previous prime is 81978089. The next prime is 81978133. The reversal of 81978112 is 21187918.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24814 + ... + 27922.

Almost surely, 2^81978112 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 81978112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82638920).

81978112 is an abundant number, since it is smaller than the sum of its proper divisors (83299728).

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

81978112 is a wasteful number, since it uses less digits than its factorization.

81978112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3228 (or 3214 counting only the distinct ones).

The product of its digits is 8064, while the sum is 37.

The square root of 81978112 is about 9054.1764948558. The cubic root of 81978112 is about 434.4094898480.

The spelling of 81978112 in words is "eighty-one million, nine hundred seventy-eight thousand, one hundred twelve".