400040 has 32 divisors (see below), whose sum is σ = 919080. Its totient is φ = 156672.

The previous prime is 400033. The next prime is 400051. The reversal of 400040 is 40004.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 343396 + 56644 = 586^2 + 238^2 .

It is a Harshad number since it is a multiple of its sum of digits (8).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2852 + ... + 2988.

2⁴⁰⁰⁰⁴⁰ is an apocalyptic number.

400040 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 400040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (459540).

400040 is an abundant number, since it is smaller than the sum of its proper divisors (519040).

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

400040 is a wasteful number, since it uses less digits than its factorization.

400040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221 (or 217 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 8.

The square root of 400040 is about 632.4871540197. The cubic root of 400040 is about 73.6830859119.

Adding to 400040 its reverse (40004), we get a palindrome (440044).

It can be divided in two parts, 4000 and 40, that multiplied together give a 4-th power (160000 = 20⁴).

The spelling of 400040 in words is "four hundred thousand, forty", and thus it is an iban number.