81659563 has 8 divisors (see below), whose sum is σ = 85226400. Its totient is φ = 78142848.

The previous prime is 81659531. The next prime is 81659597. The reversal of 81659563 is 36595618.

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 81659563 - 2⁵ = 81659531 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81659863) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9183 + ... + 15736.

It is an arithmetic number, because the mean of its divisors is an integer number (10653300).

Almost surely, 2^81659563 is an apocalyptic number.

81659563 is a deficient number, since it is larger than the sum of its proper divisors (3566837).

81659563 is a wasteful number, since it uses less digits than its factorization.

81659563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25061.

The product of its digits is 194400, while the sum is 43.

The square root of 81659563 is about 9036.5680985649. The cubic root of 81659563 is about 433.8460860638.

The spelling of 81659563 in words is "eighty-one million, six hundred fifty-nine thousand, five hundred sixty-three".