8242640 has 80 divisors (see below), whose sum is σ = 22498560. Its totient is φ = 2749440.

The previous prime is 8242639. The next prime is 8242667. The reversal of 8242640 is 462428.

It is a Cunningham number, because it is equal to 2871²-1.

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

It is a super-2 number, since 2×8242640² = 135882228339200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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, 22781 + ... + 23139.

It is an arithmetic number, because the mean of its divisors is an integer number (281232).

Almost surely, 2^8242640 is an apocalyptic number.

8242640 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 8242640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11249280).

8242640 is an abundant number, since it is smaller than the sum of its proper divisors (14255920).

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

8242640 is a wasteful number, since it uses less digits than its factorization.

8242640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 420 (or 414 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 26.

The square root of 8242640 is about 2870.9998258446. Note that the first 3 decimals coincide. The cubic root of 8242640 is about 202.0018952212.

The spelling of 8242640 in words is "eight million, two hundred forty-two thousand, six hundred forty".