404639840 has 96 divisors (see below), whose sum is σ = 1060244640. Its totient is φ = 144691200.

The previous prime is 404639819. The next prime is 404639843. The reversal of 404639840 is 48936404.

It is a junction number, because it is equal to n+sod(n) for n = 404639794 and 404639803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (404639843) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 105476 + ... + 109244.

It is an arithmetic number, because the mean of its divisors is an integer number (11044215).

Almost surely, 2^404639840 is an apocalyptic number.

404639840 is a gapful number since it is divisible by the number (40) 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 404639840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (530122320).

404639840 is an abundant number, since it is smaller than the sum of its proper divisors (655604800).

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

404639840 is a wasteful number, since it uses less digits than its factorization.

404639840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3856 (or 3848 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 38.

The square root of 404639840 is about 20115.6615600880. The cubic root of 404639840 is about 739.6442409739.

The spelling of 404639840 in words is "four hundred four million, six hundred thirty-nine thousand, eight hundred forty".