81609158 has 8 divisors (see below), whose sum is σ = 123224880. Its totient is φ = 40534200.

The previous prime is 81609131. The next prime is 81609167. The reversal of 81609158 is 85190618.

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

It is a congruent number.

It is an unprimeable number.

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, 134813 + ... + 135416.

It is an arithmetic number, because the mean of its divisors is an integer number (15403110).

Almost surely, 2^81609158 is an apocalyptic number.

81609158 is a deficient number, since it is larger than the sum of its proper divisors (41615722).

81609158 is a wasteful number, since it uses less digits than its factorization.

81609158 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 270382.

The product of its (nonzero) digits is 17280, while the sum is 38.

The square root of 81609158 is about 9033.7787221074. The cubic root of 81609158 is about 433.7568027347.

The spelling of 81609158 in words is "eighty-one million, six hundred nine thousand, one hundred fifty-eight".