321605213 has 4 divisors (see below), whose sum is σ = 329084448. Its totient is φ = 314125980.

The previous prime is 321605209. The next prime is 321605231. The reversal of 321605213 is 312506123.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 312506123 = 239 ⋅1307557.

It is a cyclic number.

It is not a de Polignac number, because 321605213 - 2² = 321605209 is a prime.

It is a super-3 number, since 3×321605213³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (321602213) 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, 3739553 + ... + 3739638.

It is an arithmetic number, because the mean of its divisors is an integer number (82271112).

Almost surely, 2^321605213 is an apocalyptic number.

It is an amenable number.

321605213 is a deficient number, since it is larger than the sum of its proper divisors (7479235).

321605213 is an equidigital number, since it uses as much as digits as its factorization.

321605213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7479234.

The product of its (nonzero) digits is 1080, while the sum is 23.

The square root of 321605213 is about 17933.3547614494. The cubic root of 321605213 is about 685.1321697829.

It can be divided in two parts, 32160 and 5213, that added together give a palindrome (37373).

The spelling of 321605213 in words is "three hundred twenty-one million, six hundred five thousand, two hundred thirteen".