321631 has 2 divisors, whose sum is σ = 321632. Its totient is φ = 321630.

The previous prime is 321619. The next prime is 321647. The reversal of 321631 is 136123.

It is an a-pointer prime, because the next prime (321647) can be obtained adding 321631 to its sum of digits (16).

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-321631 is a prime.

It is a super-2 number, since 2×321631² = 206893000322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (321611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160815 + 160816.

It is an arithmetic number, because the mean of its divisors is an integer number (160816).

2³²¹⁶³¹ is an apocalyptic number.

321631 is a deficient number, since it is larger than the sum of its proper divisors (1).

321631 is an equidigital number, since it uses as much as digits as its factorization.

321631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108, while the sum is 16.

The square root of 321631 is about 567.1252066343. The cubic root of 321631 is about 68.5150481085.

Adding to 321631 its reverse (136123), we get a palindrome (457754).

The spelling of 321631 in words is "three hundred twenty-one thousand, six hundred thirty-one".