1621366664741 has 2 divisors, whose sum is σ = 1621366664742. Its totient is φ = 1621366664740.

The previous prime is 1621366664689. The next prime is 1621366664767. The reversal of 1621366664741 is 1474666631261.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1303867096900 + 317499567841 = 1141870^2 + 563471^2 .

It is a cyclic number.

It is not a de Polignac number, because 1621366664741 - 2³⁸ = 1346488757797 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1621366664941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810683332370 + 810683332371.

It is an arithmetic number, because the mean of its divisors is an integer number (810683332371).

Almost surely, 2^{1621366664741} is an apocalyptic number.

It is an amenable number.

1621366664741 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621366664741 is an equidigital number, since it uses as much as digits as its factorization.

1621366664741 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5225472, while the sum is 53.

The spelling of 1621366664741 in words is "one trillion, six hundred twenty-one billion, three hundred sixty-six million, six hundred sixty-four thousand, seven hundred forty-one".