81217406 has 8 divisors (see below), whose sum is σ = 121884384. Its totient is φ = 40589280.

The previous prime is 81217403. The next prime is 81217417. The reversal of 81217406 is 60471218.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81217403) 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, 3755 + ... + 13286.

It is an arithmetic number, because the mean of its divisors is an integer number (15235548).

Almost surely, 2^81217406 is an apocalyptic number.

81217406 is a deficient number, since it is larger than the sum of its proper divisors (40666978).

81217406 is a wasteful number, since it uses less digits than its factorization.

81217406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19426.

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 81217406 is about 9012.0700174821. The cubic root of 81217406 is about 433.0616286219.

The spelling of 81217406 in words is "eighty-one million, two hundred seventeen thousand, four hundred six".