81860817 has 8 divisors (see below), whose sum is σ = 109758240. Its totient is φ = 54268640.

The previous prime is 81860791. The next prime is 81860843. The reversal of 81860817 is 71806818.

It is an interprime number because it is at equal distance from previous prime (81860791) and next prime (81860843).

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 81860817 - 2¹² = 81856721 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81860017) 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, 75684 + ... + 76757.

It is an arithmetic number, because the mean of its divisors is an integer number (13719780).

Almost surely, 2^81860817 is an apocalyptic number.

It is an amenable number.

81860817 is a deficient number, since it is larger than the sum of its proper divisors (27897423).

81860817 is a wasteful number, since it uses less digits than its factorization.

81860817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152623.

The product of its (nonzero) digits is 21504, while the sum is 39.

The square root of 81860817 is about 9047.6967787388. The cubic root of 81860817 is about 434.2022053220.

The spelling of 81860817 in words is "eighty-one million, eight hundred sixty thousand, eight hundred seventeen".