400400240 has 80 divisors (see below), whose sum is σ = 952171200. Its totient is φ = 156549120.

The previous prime is 400400237. The next prime is 400400249. The reversal of 400400240 is 42004004.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400400249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 891536 + ... + 891984.

It is an arithmetic number, because the mean of its divisors is an integer number (11902140).

Almost surely, 2^400400240 is an apocalyptic number.

400400240 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 400400240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (476085600).

400400240 is an abundant number, since it is smaller than the sum of its proper divisors (551770960).

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

400400240 is a wasteful number, since it uses less digits than its factorization.

400400240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 690 (or 684 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 14.

The square root of 400400240 is about 20010.0034982506. The cubic root of 400400240 is about 737.0519672691.

Adding to 400400240 its reverse (42004004), we get a palindrome (442404244).

The spelling of 400400240 in words is "four hundred million, four hundred thousand, two hundred forty".