2560639661 has 2 divisors, whose sum is σ = 2560639662. Its totient is φ = 2560639660.

The previous prime is 2560639619. The next prime is 2560639667. The reversal of 2560639661 is 1669360652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1869265225 + 691374436 = 43235^2 + 26294^2 .

It is a cyclic number.

It is not a de Polignac number, because 2560639661 - 2⁶ = 2560639597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2560639667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1280319830 + 1280319831.

It is an arithmetic number, because the mean of its divisors is an integer number (1280319831).

Almost surely, 2^2560639661 is an apocalyptic number.

It is an amenable number.

2560639661 is a deficient number, since it is larger than the sum of its proper divisors (1).

2560639661 is an equidigital number, since it uses as much as digits as its factorization.

2560639661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 349920, while the sum is 44.

The square root of 2560639661 is about 50602.7633731598. The cubic root of 2560639661 is about 1368.0946858658.

The spelling of 2560639661 in words is "two billion, five hundred sixty million, six hundred thirty-nine thousand, six hundred sixty-one".