1968444661 has 2 divisors, whose sum is σ = 1968444662. Its totient is φ = 1968444660.

The previous prime is 1968444619. The next prime is 1968444677. The reversal of 1968444661 is 1664448691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1925542161 + 42902500 = 43881^2 + 6550^2 .

It is a cyclic number.

It is not a de Polignac number, because 1968444661 - 2¹⁹ = 1967920373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1968444601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 984222330 + 984222331.

It is an arithmetic number, because the mean of its divisors is an integer number (984222331).

Almost surely, 2^1968444661 is an apocalyptic number.

It is an amenable number.

1968444661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1968444661 is an equidigital number, since it uses as much as digits as its factorization.

1968444661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 995328, while the sum is 49.

The square root of 1968444661 is about 44367.1574590935. The cubic root of 1968444661 is about 1253.2596865127.

The spelling of 1968444661 in words is "one billion, nine hundred sixty-eight million, four hundred forty-four thousand, six hundred sixty-one".