400320 has 84 divisors (see below), whose sum is σ = 1386840. Its totient is φ = 105984.

The previous prime is 400313. The next prime is 400321. The reversal of 400320 is 23004.

It is a super-2 number, since 2×400320² = 320512204800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400321) by changing a digit.

400320 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2811 + ... + 2949.

It is an arithmetic number, because the mean of its divisors is an integer number (16510).

2⁴⁰⁰³²⁰ is an apocalyptic number.

400320 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 400320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (693420).

400320 is an abundant number, since it is smaller than the sum of its proper divisors (986520).

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

400320 is a wasteful number, since it uses less digits than its factorization.

400320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 149 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 9.

The square root of 400320 is about 632.7084636703. The cubic root of 400320 is about 73.7002729036.

Adding to 400320 its reverse (23004), we get a palindrome (423324).

The spelling of 400320 in words is "four hundred thousand, three hundred twenty", and thus it is an iban number.