321240221 has 4 divisors (see below), whose sum is σ = 332317500. Its totient is φ = 310162944.

The previous prime is 321240209. The next prime is 321240233. The reversal of 321240221 is 122042123.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (321240209) and next prime (321240233).

It can be written as a sum of positive squares in 2 ways, for example, as 132480100 + 188760121 = 11510^2 + 13739^2 .

It is a cyclic number.

It is not a de Polignac number, because 321240221 - 2²² = 317045917 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 321240221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (321240421) 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, 5538596 + ... + 5538653.

It is an arithmetic number, because the mean of its divisors is an integer number (83079375).

Almost surely, 2^321240221 is an apocalyptic number.

It is an amenable number.

321240221 is a deficient number, since it is larger than the sum of its proper divisors (11077279).

321240221 is a wasteful number, since it uses less digits than its factorization.

321240221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11077278.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 321240221 is about 17923.1755277908. The cubic root of 321240221 is about 684.8728845768.

Adding to 321240221 its reverse (122042123), we get a palindrome (443282344).

The spelling of 321240221 in words is "three hundred twenty-one million, two hundred forty thousand, two hundred twenty-one".