400440420 has 36 divisors (see below), whose sum is σ = 1214669820. Its totient is φ = 106784064.

The previous prime is 400440401. The next prime is 400440421. The reversal of 400440420 is 24044004.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 107619876 + 292820544 = 10374^2 + 17112^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 400440393 and 400440402.

It is not an unprimeable number, because it can be changed into a prime (400440421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1112155 + ... + 1112514.

Almost surely, 2^400440420 is an apocalyptic number.

It is an amenable number.

400440420 is an abundant number, since it is smaller than the sum of its proper divisors (814229400).

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

400440420 is a wasteful number, since it uses less digits than its factorization.

400440420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2224684 (or 2224679 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 18.

The square root of 400440420 is about 20011.0074708896. The cubic root of 400440420 is about 737.0766207321.

Adding to 400440420 its reverse (24044004), we get a palindrome (424484424).

The spelling of 400440420 in words is "four hundred million, four hundred forty thousand, four hundred twenty".