1381455661 has 2 divisors, whose sum is σ = 1381455662. Its totient is φ = 1381455660.

The previous prime is 1381455641. The next prime is 1381455671. The reversal of 1381455661 is 1665541831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1224580036 + 156875625 = 34994^2 + 12525^2 .

It is an emirp because it is prime and its reverse (1665541831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1381455661 - 2⁷ = 1381455533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1381455641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 690727830 + 690727831.

It is an arithmetic number, because the mean of its divisors is an integer number (690727831).

Almost surely, 2^1381455661 is an apocalyptic number.

It is an amenable number.

1381455661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1381455661 is an equidigital number, since it uses as much as digits as its factorization.

1381455661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 86400, while the sum is 40.

The square root of 1381455661 is about 37167.9386165012. The cubic root of 1381455661 is about 1113.7276029478.

The spelling of 1381455661 in words is "one billion, three hundred eighty-one million, four hundred fifty-five thousand, six hundred sixty-one".