81289173 has 8 divisors (see below), whose sum is σ = 123869248. Its totient is φ = 46450944.

The previous prime is 81289151. The next prime is 81289177. The reversal of 81289173 is 37198218.

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

It is not a de Polignac number, because 81289173 - 2¹³ = 81280981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81289177) 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, 1935436 + ... + 1935477.

It is an arithmetic number, because the mean of its divisors is an integer number (15483656).

Almost surely, 2^81289173 is an apocalyptic number.

It is an amenable number.

81289173 is a deficient number, since it is larger than the sum of its proper divisors (42580075).

81289173 is a wasteful number, since it uses less digits than its factorization.

81289173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3870923.

The product of its digits is 24192, while the sum is 39.

The square root of 81289173 is about 9016.0508538938. The cubic root of 81289173 is about 433.1891480193.

The spelling of 81289173 in words is "eighty-one million, two hundred eighty-nine thousand, one hundred seventy-three".