320400020 has 48 divisors (see below), whose sum is σ = 731702160. Its totient is φ = 117356544.

The previous prime is 320400019. The next prime is 320400043. The reversal of 320400020 is 20004023.

It can be written as a sum of positive squares in 8 ways, for example, as 62283664 + 258116356 = 7892^2 + 16066^2 .

It is a junction number, because it is equal to n+sod(n) for n = 320399974 and 320400010.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 155 + ... + 25314.

It is an arithmetic number, because the mean of its divisors is an integer number (15243795).

Almost surely, 2^320400020 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 320400020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (365851080).

320400020 is an abundant number, since it is smaller than the sum of its proper divisors (411302140).

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

320400020 is a wasteful number, since it uses less digits than its factorization.

320400020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25532 (or 25530 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 11.

The square root of 320400020 is about 17899.7212268795. The cubic root of 320400020 is about 684.2752702338.

Adding to 320400020 its reverse (20004023), we get a palindrome (340404043).

The spelling of 320400020 in words is "three hundred twenty million, four hundred thousand, twenty".