408400840 has 32 divisors (see below), whose sum is σ = 920911680. Its totient is φ = 163003072.

The previous prime is 408400831. The next prime is 408400841. The reversal of 408400840 is 48004804.

It is a happy number.

It is a super-2 number, since 2×408400840² = 333582492225411200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 408400799 and 408400808.

It is not an unprimeable number, because it can be changed into a prime (408400841) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7749 + ... + 29611.

It is an arithmetic number, because the mean of its divisors is an integer number (28778490).

Almost surely, 2^408400840 is an apocalyptic number.

408400840 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

408400840 is an abundant number, since it is smaller than the sum of its proper divisors (512510840).

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

408400840 is a wasteful number, since it uses less digits than its factorization.

408400840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22341 (or 22337 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 28.

The square root of 408400840 is about 20208.9297094131. The cubic root of 408400840 is about 741.9287643849.

The spelling of 408400840 in words is "four hundred eight million, four hundred thousand, eight hundred forty".