81704159 has 4 divisors (see below), whose sum is σ = 86510304. Its totient is φ = 76898016.

The previous prime is 81704153. The next prime is 81704191. The reversal of 81704159 is 95140718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 95140718 = 2 ⋅47570359.

It is a cyclic number.

It is not a de Polignac number, because 81704159 - 2⁴ = 81704143 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81704153) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2403047 + ... + 2403080.

It is an arithmetic number, because the mean of its divisors is an integer number (21627576).

Almost surely, 2^81704159 is an apocalyptic number.

81704159 is a deficient number, since it is larger than the sum of its proper divisors (4806145).

81704159 is a wasteful number, since it uses less digits than its factorization.

81704159 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4806144.

The product of its (nonzero) digits is 10080, while the sum is 35.

The square root of 81704159 is about 9039.0352914457. The cubic root of 81704159 is about 433.9250491733.

The spelling of 81704159 in words is "eighty-one million, seven hundred four thousand, one hundred fifty-nine".