321440031315661 has 2 divisors, whose sum is σ = 321440031315662. Its totient is φ = 321440031315660.

The previous prime is 321440031315647. The next prime is 321440031315797. The reversal of 321440031315661 is 166513130044123.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 311659832132100 + 9780199183561 = 17653890^2 + 3127331^2 .

It is a cyclic number.

It is not a de Polignac number, because 321440031315661 - 2¹³ = 321440031307469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (321440031315061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160720015657830 + 160720015657831.

It is an arithmetic number, because the mean of its divisors is an integer number (160720015657831).

Almost surely, 2^{321440031315661} is an apocalyptic number.

It is an amenable number.

321440031315661 is a deficient number, since it is larger than the sum of its proper divisors (1).

321440031315661 is an equidigital number, since it uses as much as digits as its factorization.

321440031315661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 155520, while the sum is 40.

Adding to 321440031315661 its reverse (166513130044123), we get a palindrome (487953161359784).

The spelling of 321440031315661 in words is "three hundred twenty-one trillion, four hundred forty billion, thirty-one million, three hundred fifteen thousand, six hundred sixty-one".