400720 has 20 divisors (see below), whose sum is σ = 931860. Its totient is φ = 160256.

The previous prime is 400711. The next prime is 400721. The reversal of 400720 is 27004.

It can be written as a sum of positive squares in 2 ways, for example, as 166464 + 234256 = 408^2 + 484^2 .

It is a tau number, because it is divible by the number of its divisors (20).

400720 is a modest number, since divided by 720 gives 400 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 400720.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2425 + ... + 2584.

It is an arithmetic number, because the mean of its divisors is an integer number (46593).

2⁴⁰⁰⁷²⁰ is an apocalyptic number.

400720 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

400720 is an abundant number, since it is smaller than the sum of its proper divisors (531140).

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

400720 is a wasteful number, since it uses less digits than its factorization.

400720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5022 (or 5016 counting only the distinct ones).

The product of its (nonzero) digits is 56, while the sum is 13.

The square root of 400720 is about 633.0244860983. The cubic root of 400720 is about 73.7248118523.

Adding to 400720 its reverse (27004), we get a palindrome (427724).

The spelling of 400720 in words is "four hundred thousand, seven hundred twenty", and thus it is an iban number.