81702709 has 24 divisors (see below), whose sum is σ = 94381056. Its totient is φ = 70593600.

The previous prime is 81702689. The next prime is 81702713. The reversal of 81702709 is 90720718.

It is not a de Polignac number, because 81702709 - 2²¹ = 79605557 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81702749) 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 23 ways as a sum of consecutive naturals, for example, 213132 + ... + 213514.

It is an arithmetic number, because the mean of its divisors is an integer number (3932544).

Almost surely, 2^81702709 is an apocalyptic number.

It is an amenable number.

81702709 is a deficient number, since it is larger than the sum of its proper divisors (12678347).

81702709 is a wasteful number, since it uses less digits than its factorization.

81702709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 489 (or 478 counting only the distinct ones).

The product of its (nonzero) digits is 7056, while the sum is 34.

The square root of 81702709 is about 9038.9550834153. The cubic root of 81702709 is about 433.9224822088.

Subtracting 81702709 from its reverse (90720718), we obtain a square (9018009 = 3003²).

The spelling of 81702709 in words is "eighty-one million, seven hundred two thousand, seven hundred nine".