1338661861 has 2 divisors, whose sum is σ = 1338661862. Its totient is φ = 1338661860.

The previous prime is 1338661781. The next prime is 1338661901. The reversal of 1338661861 is 1681668331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1128556836 + 210105025 = 33594^2 + 14495^2 .

It is a cyclic number.

It is not a de Polignac number, because 1338661861 - 2¹⁵ = 1338629093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1338661361) 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, 669330930 + 669330931.

It is an arithmetic number, because the mean of its divisors is an integer number (669330931).

Almost surely, 2^1338661861 is an apocalyptic number.

It is an amenable number.

1338661861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1338661861 is an equidigital number, since it uses as much as digits as its factorization.

1338661861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 124416, while the sum is 43.

The square root of 1338661861 is about 36587.7282842212. The cubic root of 1338661861 is about 1102.1066683417.

The spelling of 1338661861 in words is "one billion, three hundred thirty-eight million, six hundred sixty-one thousand, eight hundred sixty-one".