321312440 has 64 divisors (see below), whose sum is σ = 749800800. Its totient is φ = 123821568.

The previous prime is 321312389. The next prime is 321312487. The reversal of 321312440 is 44213123.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 157346 + ... + 159374.

Almost surely, 2^321312440 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 321312440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (374900400).

321312440 is an abundant number, since it is smaller than the sum of its proper divisors (428488360).

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

321312440 is a wasteful number, since it uses less digits than its factorization.

321312440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2184 (or 2180 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 321312440 is about 17925.1900966210. The cubic root of 321312440 is about 684.9242035230.

Adding to 321312440 its reverse (44213123), we get a palindrome (365525563).

The spelling of 321312440 in words is "three hundred twenty-one million, three hundred twelve thousand, four hundred forty".