81706619 has 8 divisors (see below), whose sum is σ = 84980160. Its totient is φ = 78489216.

The previous prime is 81706613. The next prime is 81706621. The reversal of 81706619 is 91660718.

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 81706619 - 2⁸ = 81706363 is a prime.

It is a super-2 number, since 2×81706619² = 13351943176822322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81706613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11054 + ... + 16899.

It is an arithmetic number, because the mean of its divisors is an integer number (10622520).

Almost surely, 2^81706619 is an apocalyptic number.

81706619 is a deficient number, since it is larger than the sum of its proper divisors (3273541).

81706619 is a wasteful number, since it uses less digits than its factorization.

81706619 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28069.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 81706619 is about 9039.1713668898. The cubic root of 81706619 is about 433.9294040920.

The spelling of 81706619 in words is "eighty-one million, seven hundred six thousand, six hundred nineteen".