321540 has 48 divisors (see below), whose sum is σ = 943488. Its totient is φ = 81664.

The previous prime is 321509. The next prime is 321547. The reversal of 321540 is 45123.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a nialpdrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 321540.

It is not an unprimeable number, because it can be changed into a prime (321547) by changing a digit.

321540 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 15 ways as a sum of consecutive naturals, for example, 1264 + ... + 1496.

It is an arithmetic number, because the mean of its divisors is an integer number (19656).

2³²¹⁵⁴⁰ is an apocalyptic number.

321540 is a gapful number since it is divisible by the number (30) 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 321540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (471744).

321540 is an abundant number, since it is smaller than the sum of its proper divisors (621948).

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

321540 is a wasteful number, since it uses less digits than its factorization.

321540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 268 (or 266 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 321540 is about 567.0449717615. The cubic root of 321540 is about 68.5085857780.

Adding to 321540 its reverse (45123), we get a palindrome (366663).

It can be divided in two parts, 321 and 540, that added together give a triangular number (861 = T₄₁).

The spelling of 321540 in words is "three hundred twenty-one thousand, five hundred forty".