81715738 has 16 divisors (see below), whose sum is σ = 135074016. Its totient is φ = 36837360.

The previous prime is 81715729. The next prime is 81715763. The reversal of 81715738 is 83751718.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 81715738.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35428 + ... + 37663.

It is an arithmetic number, because the mean of its divisors is an integer number (8442126).

Almost surely, 2^81715738 is an apocalyptic number.

81715738 is a deficient number, since it is larger than the sum of its proper divisors (53358278).

81715738 is a wasteful number, since it uses less digits than its factorization.

81715738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73149.

The product of its digits is 47040, while the sum is 40.

The square root of 81715738 is about 9039.6757685218. The cubic root of 81715738 is about 433.9455466236.

The spelling of 81715738 in words is "eighty-one million, seven hundred fifteen thousand, seven hundred thirty-eight".