81239788 has 24 divisors (see below), whose sum is σ = 168084000. Its totient is φ = 33616128.

The previous prime is 81239779. The next prime is 81239789. The reversal of 81239788 is 88793218.

It is not an unprimeable number, because it can be changed into a prime (81239789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49213 + ... + 50836.

It is an arithmetic number, because the mean of its divisors is an integer number (7003500).

Almost surely, 2^81239788 is an apocalyptic number.

It is an amenable number.

81239788 is an abundant number, since it is smaller than the sum of its proper divisors (86844212).

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

81239788 is a wasteful number, since it uses less digits than its factorization.

81239788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100089 (or 100087 counting only the distinct ones).

The product of its digits is 193536, while the sum is 46.

The square root of 81239788 is about 9013.3117110194. The cubic root of 81239788 is about 433.1014061999.

It can be divided in two parts, 812 and 39788, that multiplied together give a square (32307856 = 5684²).

The spelling of 81239788 in words is "eighty-one million, two hundred thirty-nine thousand, seven hundred eighty-eight".