81938137 has 8 divisors (see below), whose sum is σ = 85377600. Its totient is φ = 78539664.

The previous prime is 81938111. The next prime is 81938141. The reversal of 81938137 is 73183918.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81938137 - 2⁷ = 81938009 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81938137.

It is not an unprimeable number, because it can be changed into a prime (81938737) by changing a digit.

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, 6133 + ... + 14194.

It is an arithmetic number, because the mean of its divisors is an integer number (10672200).

Almost surely, 2^81938137 is an apocalyptic number.

It is an amenable number.

81938137 is a deficient number, since it is larger than the sum of its proper divisors (3439463).

81938137 is a wasteful number, since it uses less digits than its factorization.

81938137 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20495.

The product of its digits is 36288, while the sum is 40.

The square root of 81938137 is about 9051.9686809003. The cubic root of 81938137 is about 434.3388679778.

The spelling of 81938137 in words is "eighty-one million, nine hundred thirty-eight thousand, one hundred thirty-seven".