8217840 has 80 divisors (see below), whose sum is σ = 25810848. Its totient is φ = 2162688.

The previous prime is 8217827. The next prime is 8217841. The reversal of 8217840 is 487128.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 8217798 and 8217807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8217841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23104 + ... + 23456.

Almost surely, 2^8217840 is an apocalyptic number.

8217840 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 8217840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12905424).

8217840 is an abundant number, since it is smaller than the sum of its proper divisors (17593008).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

8217840 is a wasteful number, since it uses less digits than its factorization.

8217840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 466 (or 460 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 30.

The square root of 8217840 is about 2866.6775193593. The cubic root of 8217840 is about 201.7991009844.

The spelling of 8217840 in words is "eight million, two hundred seventeen thousand, eight hundred forty".