81289838 has 16 divisors (see below), whose sum is σ = 139488480. Its totient is φ = 34804896.

The previous prime is 81289799. The next prime is 81289849. The reversal of 81289838 is 83898218.

It is a junction number, because it is equal to n+sod(n) for n = 81289792 and 81289801.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17108 + ... + 21336.

It is an arithmetic number, because the mean of its divisors is an integer number (8718030).

Almost surely, 2^81289838 is an apocalyptic number.

81289838 is a deficient number, since it is larger than the sum of its proper divisors (58198642).

81289838 is a wasteful number, since it uses less digits than its factorization.

81289838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5611.

The product of its digits is 221184, while the sum is 47.

The square root of 81289838 is about 9016.0877324924. The cubic root of 81289838 is about 433.1903292754.

The spelling of 81289838 in words is "eighty-one million, two hundred eighty-nine thousand, eight hundred thirty-eight".