81670903 has 4 divisors (see below), whose sum is σ = 81937240. Its totient is φ = 81404568.

The previous prime is 81670891. The next prime is 81670909. The reversal of 81670903 is 30907618.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81670903 - 2⁵ = 81670871 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81670909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 132708 + ... + 133321.

It is an arithmetic number, because the mean of its divisors is an integer number (20484310).

Almost surely, 2^81670903 is an apocalyptic number.

81670903 is a deficient number, since it is larger than the sum of its proper divisors (266337).

81670903 is a wasteful number, since it uses less digits than its factorization.

81670903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266336.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 81670903 is about 9037.1955273746. The cubic root of 81670903 is about 433.8661677571.

The spelling of 81670903 in words is "eighty-one million, six hundred seventy thousand, nine hundred three".