81137944 has 16 divisors (see below), whose sum is σ = 152547120. Its totient is φ = 40458720.

The previous prime is 81137909. The next prime is 81137971. The reversal of 81137944 is 44973118.

It is a congruent number.

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, 10612 + ... + 16579.

It is an arithmetic number, because the mean of its divisors is an integer number (9534195).

Almost surely, 2^81137944 is an apocalyptic number.

It is an amenable number.

81137944 is a deficient number, since it is larger than the sum of its proper divisors (71409176).

81137944 is a wasteful number, since it uses less digits than its factorization.

81137944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27570 (or 27566 counting only the distinct ones).

The product of its digits is 24192, while the sum is 37.

The square root of 81137944 is about 9007.6602955485. The cubic root of 81137944 is about 432.9203486768.

The spelling of 81137944 in words is "eighty-one million, one hundred thirty-seven thousand, nine hundred forty-four".