81912617 has 8 divisors (see below), whose sum is σ = 85760640. Its totient is φ = 78132880.

The previous prime is 81912599. The next prime is 81912631. The reversal of 81912617 is 71621918.

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

It is not a de Polignac number, because 81912617 - 2¹⁴ = 81896233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81912217) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 14609 + ... + 19422.

It is an arithmetic number, because the mean of its divisors is an integer number (10720080).

Almost surely, 2^81912617 is an apocalyptic number.

It is an amenable number.

81912617 is a deficient number, since it is larger than the sum of its proper divisors (3848023).

81912617 is a wasteful number, since it uses less digits than its factorization.

81912617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34143.

The product of its digits is 6048, while the sum is 35.

The square root of 81912617 is about 9050.5589330162. The cubic root of 81912617 is about 434.2937710332.

The spelling of 81912617 in words is "eighty-one million, nine hundred twelve thousand, six hundred seventeen".