81659473 has 8 divisors (see below), whose sum is σ = 98237120. Its totient is φ = 66309840.

The previous prime is 81659471. The next prime is 81659521. The reversal of 81659473 is 37495618.

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 81659473 - 2¹ = 81659471 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81659471) 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, 306858 + ... + 307123.

It is an arithmetic number, because the mean of its divisors is an integer number (12279640).

Almost surely, 2^81659473 is an apocalyptic number.

It is an amenable number.

81659473 is a deficient number, since it is larger than the sum of its proper divisors (16577647).

81659473 is a wasteful number, since it uses less digits than its factorization.

81659473 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 614007.

The product of its digits is 181440, while the sum is 43.

The square root of 81659473 is about 9036.5631187969. The cubic root of 81659473 is about 433.8459266779.

The spelling of 81659473 in words is "eighty-one million, six hundred fifty-nine thousand, four hundred seventy-three".