400840000 has 140 divisors (see below), whose sum is σ = 1085502528. Its totient is φ = 145600000.

The previous prime is 400839977. The next prime is 400840009. The reversal of 400840000 is 48004.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400840009) 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 19 ways as a sum of consecutive naturals, for example, 439545 + ... + 440455.

Almost surely, 2^400840000 is an apocalyptic number.

400840000 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 400840000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (542751264).

400840000 is an abundant number, since it is smaller than the sum of its proper divisors (684662528).

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

400840000 is an equidigital number, since it uses as much as digits as its factorization.

400840000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 954 (or 929 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 400840000 is about 20020.9889865611. The cubic root of 400840000 is about 737.3217035234.

Adding to 400840000 its reverse (48004), we get a palindrome (400888004).

The spelling of 400840000 in words is "four hundred million, eight hundred forty thousand".