81327909 has 8 divisors (see below), whose sum is σ = 116778592. Its totient is φ = 50047920.

The previous prime is 81327871. The next prime is 81327937. The reversal of 81327909 is 90972318.

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

It is not a de Polignac number, because 81327909 - 2⁷ = 81327781 is a prime.

It is a super-2 number, since 2×81327909² = 13228457564624562, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 2085331 = 81327909 / (8 + 1 + 3 + 2 + 7 + 9 + 0 + 9).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81327209) 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, 1042627 + ... + 1042704.

It is an arithmetic number, because the mean of its divisors is an integer number (14597324).

Almost surely, 2^81327909 is an apocalyptic number.

It is an amenable number.

81327909 is a deficient number, since it is larger than the sum of its proper divisors (35450683).

81327909 is a wasteful number, since it uses less digits than its factorization.

81327909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2085347.

The product of its (nonzero) digits is 27216, while the sum is 39.

The square root of 81327909 is about 9018.1987669379. The cubic root of 81327909 is about 433.2579450049.

The spelling of 81327909 in words is "eighty-one million, three hundred twenty-seven thousand, nine hundred nine".