81386788 has 48 divisors (see below), whose sum is σ = 173859840. Its totient is φ = 32576544.

The previous prime is 81386771. The next prime is 81386797. The reversal of 81386788 is 88768318.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26223 + ... + 29161.

It is an arithmetic number, because the mean of its divisors is an integer number (3622080).

Almost surely, 2^81386788 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 81386788, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86929920).

81386788 is an abundant number, since it is smaller than the sum of its proper divisors (92473052).

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

81386788 is a wasteful number, since it uses less digits than its factorization.

81386788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3016 (or 3014 counting only the distinct ones).

The product of its digits is 516096, while the sum is 49.

The square root of 81386788 is about 9021.4626308598. The cubic root of 81386788 is about 433.3624750947.

The spelling of 81386788 in words is "eighty-one million, three hundred eighty-six thousand, seven hundred eighty-eight".