321213531531 has 4 divisors (see below), whose sum is σ = 428284708712. Its totient is φ = 214142354352.

The previous prime is 321213531481. The next prime is 321213531599. The reversal of 321213531531 is 135135312123.

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

It is not a de Polignac number, because 321213531531 - 2¹⁰ = 321213530507 is a prime.

It is a super-2 number, since 2×321213531531² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (321213531131) 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, 53535588586 + ... + 53535588591.

It is an arithmetic number, because the mean of its divisors is an integer number (107071177178).

Almost surely, 2^321213531531 is an apocalyptic number.

321213531531 is a deficient number, since it is larger than the sum of its proper divisors (107071177181).

321213531531 is a wasteful number, since it uses less digits than its factorization.

321213531531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107071177180.

The product of its digits is 8100, while the sum is 30.

Adding to 321213531531 its reverse (135135312123), we get a palindrome (456348843654).

The spelling of 321213531531 in words is "three hundred twenty-one billion, two hundred thirteen million, five hundred thirty-one thousand, five hundred thirty-one".