641322231661 has 2 divisors, whose sum is σ = 641322231662. Its totient is φ = 641322231660.

The previous prime is 641322231659. The next prime is 641322231689. The reversal of 641322231661 is 166132223146.

641322231661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 548651304100 + 92670927561 = 740710^2 + 304419^2 .

It is a cyclic number.

It is not a de Polignac number, because 641322231661 - 2¹ = 641322231659 is a prime.

It is a super-2 number, since 2×641322231661² (a number of 24 digits) contains 22 as substring.

Together with 641322231659, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 641322231661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (641322231611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320661115830 + 320661115831.

It is an arithmetic number, because the mean of its divisors is an integer number (320661115831).

Almost surely, 2^641322231661 is an apocalyptic number.

It is an amenable number.

641322231661 is a deficient number, since it is larger than the sum of its proper divisors (1).

641322231661 is an equidigital number, since it uses as much as digits as its factorization.

641322231661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 62208, while the sum is 37.

The spelling of 641322231661 in words is "six hundred forty-one billion, three hundred twenty-two million, two hundred thirty-one thousand, six hundred sixty-one".