81704161 has 24 divisors (see below), whose sum is σ = 108059840. Its totient is φ = 60302880.

The previous prime is 81704153. The next prime is 81704191. The reversal of 81704161 is 16140718.

It is not a de Polignac number, because 81704161 - 2³ = 81704153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81704131) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13555 + ... + 18631.

Almost surely, 2^81704161 is an apocalyptic number.

It is an amenable number.

81704161 is a deficient number, since it is larger than the sum of its proper divisors (26355679).

81704161 is a wasteful number, since it uses less digits than its factorization.

81704161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5125 (or 5114 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 28.

The square root of 81704161 is about 9039.0354020769. The cubic root of 81704161 is about 433.9250527139.

Adding to 81704161 its reverse (16140718), we get a palindrome (97844879).

The spelling of 81704161 in words is "eighty-one million, seven hundred four thousand, one hundred sixty-one".