8409840 has 80 divisors (see below), whose sum is σ = 26510208. Its totient is φ = 2204928.

The previous prime is 8409839. The next prime is 8409857. The reversal of 8409840 is 489048.

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

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15819 + ... + 16341.

Almost surely, 2^8409840 is an apocalyptic number.

8409840 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 8409840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13255104).

8409840 is an abundant number, since it is smaller than the sum of its proper divisors (18100368).

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

8409840 is a wasteful number, since it uses less digits than its factorization.

8409840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 606 (or 600 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 8409840 is about 2899.9724136619. The cubic root of 8409840 is about 203.3586161043.

The spelling of 8409840 in words is "eight million, four hundred nine thousand, eight hundred forty".