81137158 has 16 divisors (see below), whose sum is σ = 129037104. Its totient is φ = 38131200.

The previous prime is 81137153. The next prime is 81137159. The reversal of 81137158 is 85173118.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81137153) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39841 + ... + 41827.

It is an arithmetic number, because the mean of its divisors is an integer number (8064819).

Almost surely, 2^81137158 is an apocalyptic number.

81137158 is a deficient number, since it is larger than the sum of its proper divisors (47899946).

81137158 is a wasteful number, since it uses less digits than its factorization.

81137158 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3207.

The product of its digits is 6720, while the sum is 34.

The square root of 81137158 is about 9007.6166659111. The cubic root of 81137158 is about 432.9189507428.

The spelling of 81137158 in words is "eighty-one million, one hundred thirty-seven thousand, one hundred fifty-eight".