81650671 has 4 divisors (see below), whose sum is σ = 82107000. Its totient is φ = 81194344.

The previous prime is 81650663. The next prime is 81650707. The reversal of 81650671 is 17605618.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17605618 = 2 ⋅8802809.

It is a cyclic number.

It is not a de Polignac number, because 81650671 - 2³ = 81650663 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 (81650651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 227896 + ... + 228253.

It is an arithmetic number, because the mean of its divisors is an integer number (20526750).

Almost surely, 2^81650671 is an apocalyptic number.

81650671 is a deficient number, since it is larger than the sum of its proper divisors (456329).

81650671 is a wasteful number, since it uses less digits than its factorization.

81650671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 456328.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 81650671 is about 9036.0760842304. The cubic root of 81650671 is about 433.8303381657.

The spelling of 81650671 in words is "eighty-one million, six hundred fifty thousand, six hundred seventy-one".