1661384801 has 2 divisors, whose sum is σ = 1661384802. Its totient is φ = 1661384800.

The previous prime is 1661384761. The next prime is 1661384819. The reversal of 1661384801 is 1084831661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1358659600 + 302725201 = 36860^2 + 17399^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661384801 - 2¹⁸ = 1661122657 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1661384201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830692400 + 830692401.

It is an arithmetic number, because the mean of its divisors is an integer number (830692401).

Almost surely, 2^1661384801 is an apocalyptic number.

It is an amenable number.

1661384801 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661384801 is an equidigital number, since it uses as much as digits as its factorization.

1661384801 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 1661384801 is about 40760.0883340554. The cubic root of 1661384801 is about 1184.3773072462.

The spelling of 1661384801 in words is "one billion, six hundred sixty-one million, three hundred eighty-four thousand, eight hundred one".