400003920 has 100 divisors (see below), whose sum is σ = 1389295380. Its totient is φ = 106665984.

The previous prime is 400003909. The next prime is 400003921. The reversal of 400003920 is 29300004.

It can be written as a sum of positive squares in 2 ways, for example, as 299843856 + 100160064 = 17316^2 + 10008^2 .

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 = 400003893 and 400003902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400003921) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 24385 + ... + 37344.

Almost surely, 2^400003920 is an apocalyptic number.

400003920 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

400003920 is an abundant number, since it is smaller than the sum of its proper divisors (989291460).

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

400003920 is a wasteful number, since it uses less digits than its factorization.

400003920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61754 (or 61739 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 400003920 is about 20000.0979997599. The cubic root of 400003920 is about 736.8087066208.

Adding to 400003920 its reverse (29300004), we get a palindrome (429303924).

The spelling of 400003920 in words is "four hundred million, three thousand, nine hundred twenty".