1338705661 has 2 divisors, whose sum is σ = 1338705662. Its totient is φ = 1338705660.

The previous prime is 1338705631. The next prime is 1338705673. The reversal of 1338705661 is 1665078331.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1142845636 + 195860025 = 33806^2 + 13995^2 .

It is a cyclic number.

It is not a de Polignac number, because 1338705661 - 2¹³ = 1338697469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1338705601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 669352830 + 669352831.

It is an arithmetic number, because the mean of its divisors is an integer number (669352831).

Almost surely, 2^1338705661 is an apocalyptic number.

It is an amenable number.

1338705661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1338705661 is an equidigital number, since it uses as much as digits as its factorization.

1338705661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 90720, while the sum is 40.

The square root of 1338705661 is about 36588.3268406742. The cubic root of 1338705661 is about 1102.1186882419.

The spelling of 1338705661 in words is "one billion, three hundred thirty-eight million, seven hundred five thousand, six hundred sixty-one".