81758138 has 16 divisors (see below), whose sum is σ = 152898624. Its totient is φ = 31853760.

The previous prime is 81758137. The next prime is 81758143. The reversal of 81758138 is 83185718.

It is a junction number, because it is equal to n+sod(n) for n = 81758095 and 81758104.

It is not an unprimeable number, because it can be changed into a prime (81758137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 265295 + ... + 265602.

It is an arithmetic number, because the mean of its divisors is an integer number (9556164).

Almost surely, 2^81758138 is an apocalyptic number.

81758138 is a deficient number, since it is larger than the sum of its proper divisors (71140486).

81758138 is a wasteful number, since it uses less digits than its factorization.

81758138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 530917.

The product of its digits is 53760, while the sum is 41.

The square root of 81758138 is about 9042.0206812416. The cubic root of 81758138 is about 434.0205876959.

The spelling of 81758138 in words is "eighty-one million, seven hundred fifty-eight thousand, one hundred thirty-eight".