81139118 has 8 divisors (see below), whose sum is σ = 122455848. Its totient is φ = 40320504.

The previous prime is 81139111. The next prime is 81139133. The reversal of 81139118 is 81193118.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81139111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 124121 + ... + 124772.

It is an arithmetic number, because the mean of its divisors is an integer number (15306981).

Almost surely, 2^81139118 is an apocalyptic number.

81139118 is a deficient number, since it is larger than the sum of its proper divisors (41316730).

81139118 is a wasteful number, since it uses less digits than its factorization.

81139118 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249058.

The product of its digits is 1728, while the sum is 32.

The square root of 81139118 is about 9007.7254620687. The cubic root of 81139118 is about 432.9224366684.

The spelling of 81139118 in words is "eighty-one million, one hundred thirty-nine thousand, one hundred eighteen".