2643316661 has 2 divisors, whose sum is σ = 2643316662. Its totient is φ = 2643316660.

The previous prime is 2643316633. The next prime is 2643316673. The reversal of 2643316661 is 1666133462.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1613548561 + 1029768100 = 40169^2 + 32090^2 .

It is a cyclic number.

It is not a de Polignac number, because 2643316661 - 2³⁰ = 1569574837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2643316601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1321658330 + 1321658331.

It is an arithmetic number, because the mean of its divisors is an integer number (1321658331).

Almost surely, 2^2643316661 is an apocalyptic number.

It is an amenable number.

2643316661 is a deficient number, since it is larger than the sum of its proper divisors (1).

2643316661 is an equidigital number, since it uses as much as digits as its factorization.

2643316661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 38.

The square root of 2643316661 is about 51413.1953976798. The cubic root of 2643316661 is about 1382.6631798379.

The spelling of 2643316661 in words is "two billion, six hundred forty-three million, three hundred sixteen thousand, six hundred sixty-one".