82391681 has 8 divisors (see below), whose sum is σ = 86354880. Its totient is φ = 78460272.

The previous prime is 82391677. The next prime is 82391689. The reversal of 82391681 is 18619328.

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 82391681 - 2² = 82391677 is a prime.

It is a super-2 number, since 2×82391681² = 13576778196011522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (82391689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2555 + ... + 13088.

It is an arithmetic number, because the mean of its divisors is an integer number (10794360).

Almost surely, 2^82391681 is an apocalyptic number.

It is an amenable number.

82391681 is a deficient number, since it is larger than the sum of its proper divisors (3963199).

82391681 is a wasteful number, since it uses less digits than its factorization.

82391681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15895.

The product of its digits is 20736, while the sum is 38.

The square root of 82391681 is about 9076.9863390885. The cubic root of 82391681 is about 435.1387781105.

The spelling of 82391681 in words is "eighty-two million, three hundred ninety-one thousand, six hundred eighty-one".