2631663220561 has 2 divisors, whose sum is σ = 2631663220562. Its totient is φ = 2631663220560.

The previous prime is 2631663220559. The next prime is 2631663220609. The reversal of 2631663220561 is 1650223661362.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2254322073600 + 377341146961 = 1501440^2 + 614281^2 .

It is a cyclic number.

It is not a de Polignac number, because 2631663220561 - 2¹ = 2631663220559 is a prime.

Together with 2631663220559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (2631663227561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1315831610280 + 1315831610281.

It is an arithmetic number, because the mean of its divisors is an integer number (1315831610281).

Almost surely, 2^{2631663220561} is an apocalyptic number.

It is an amenable number.

2631663220561 is a deficient number, since it is larger than the sum of its proper divisors (1).

2631663220561 is an equidigital number, since it uses as much as digits as its factorization.

2631663220561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 466560, while the sum is 43.

The spelling of 2631663220561 in words is "two trillion, six hundred thirty-one billion, six hundred sixty-three million, two hundred twenty thousand, five hundred sixty-one".