81351138 has 32 divisors (see below), whose sum is σ = 185213952. Its totient is φ = 23579600.

The previous prime is 81351133. The next prime is 81351173. The reversal of 81351138 is 83115318.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81351133) 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 15 ways as a sum of consecutive naturals, for example, 25278 + ... + 28313.

It is an arithmetic number, because the mean of its divisors is an integer number (5787936).

Almost surely, 2^81351138 is an apocalyptic number.

81351138 is an abundant number, since it is smaller than the sum of its proper divisors (103862814).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81351138 is a wasteful number, since it uses less digits than its factorization.

81351138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53630.

The product of its digits is 2880, while the sum is 30.

The square root of 81351138 is about 9019.4865707533. The cubic root of 81351138 is about 433.2991903408.

The spelling of 81351138 in words is "eighty-one million, three hundred fifty-one thousand, one hundred thirty-eight".