81635 has 8 divisors (see below), whose sum is σ = 101520. Its totient is φ = 62944.

The previous prime is 81629. The next prime is 81637. The reversal of 81635 is 53618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81635 - 2⁴ = 81619 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81635.

It is not an unprimeable number, because it can be changed into a prime (81637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 137 + ... + 426.

It is an arithmetic number, because the mean of its divisors is an integer number (12690).

2⁸¹⁶³⁵ is an apocalyptic number.

81635 is a deficient number, since it is larger than the sum of its proper divisors (19885).

81635 is a wasteful number, since it uses less digits than its factorization.

81635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 597.

The product of its digits is 720, while the sum is 23.

The square root of 81635 is about 285.7183928276. The cubic root of 81635 is about 43.3802581749.

The spelling of 81635 in words is "eighty-one thousand, six hundred thirty-five".