81795647 has 4 divisors (see below), whose sum is σ = 82114176. Its totient is φ = 81477120.

The previous prime is 81795617. The next prime is 81795667. The reversal of 81795647 is 74659718.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81795647 - 2¹⁴ = 81779263 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 (81795617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 158879 + ... + 159392.

It is an arithmetic number, because the mean of its divisors is an integer number (20528544).

Almost surely, 2^81795647 is an apocalyptic number.

81795647 is a deficient number, since it is larger than the sum of its proper divisors (318529).

81795647 is a wasteful number, since it uses less digits than its factorization.

81795647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318528.

The product of its digits is 423360, while the sum is 47.

The square root of 81795647 is about 9044.0945926057. The cubic root of 81795647 is about 434.0869508725.

The spelling of 81795647 in words is "eighty-one million, seven hundred ninety-five thousand, six hundred forty-seven".