81659463 has 4 divisors (see below), whose sum is σ = 108879288. Its totient is φ = 54439640.

The previous prime is 81659429. The next prime is 81659471. The reversal of 81659463 is 36495618.

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 81659463 - 2¹⁸ = 81397319 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81659863) 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, 13609908 + ... + 13609913.

It is an arithmetic number, because the mean of its divisors is an integer number (27219822).

Almost surely, 2^81659463 is an apocalyptic number.

81659463 is a deficient number, since it is larger than the sum of its proper divisors (27219825).

81659463 is a wasteful number, since it uses less digits than its factorization.

81659463 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27219824.

The product of its digits is 155520, while the sum is 42.

The square root of 81659463 is about 9036.5625654892. The cubic root of 81659463 is about 433.8459089683.

The spelling of 81659463 in words is "eighty-one million, six hundred fifty-nine thousand, four hundred sixty-three".