81715329 has 6 divisors (see below), whose sum is σ = 118033266. Its totient is φ = 54476880.

The previous prime is 81715307. The next prime is 81715331. The reversal of 81715329 is 92351718.

It can be written as a sum of positive squares in only one way, i.e., 43560000 + 38155329 = 6600^2 + 6177^2 .

It is not a de Polignac number, because 81715329 - 2⁷ = 81715201 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81715293 and 81715302.

It is not an unprimeable number, because it can be changed into a prime (81715399) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4539732 + ... + 4539749.

It is an arithmetic number, because the mean of its divisors is an integer number (19672211).

Almost surely, 2^81715329 is an apocalyptic number.

It is an amenable number.

81715329 is a deficient number, since it is larger than the sum of its proper divisors (36317937).

81715329 is a wasteful number, since it uses less digits than its factorization.

81715329 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9079487 (or 9079484 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 81715329 is about 9039.6531460007. The cubic root of 81715329 is about 433.9448226340.

The spelling of 81715329 in words is "eighty-one million, seven hundred fifteen thousand, three hundred twenty-nine".