1388085661 has 2 divisors, whose sum is σ = 1388085662. Its totient is φ = 1388085660.

The previous prime is 1388085653. The next prime is 1388085697. The reversal of 1388085661 is 1665808831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1239392025 + 148693636 = 35205^2 + 12194^2 .

It is a cyclic number.

It is not a de Polignac number, because 1388085661 - 2³ = 1388085653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1388085631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 694042830 + 694042831.

It is an arithmetic number, because the mean of its divisors is an integer number (694042831).

Almost surely, 2^1388085661 is an apocalyptic number.

It is an amenable number.

1388085661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1388085661 is an equidigital number, since it uses as much as digits as its factorization.

1388085661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 276480, while the sum is 46.

The square root of 1388085661 is about 37257.0216335123. The cubic root of 1388085661 is about 1115.5064591083.

The spelling of 1388085661 in words is "one billion, three hundred eighty-eight million, eighty-five thousand, six hundred sixty-one".