1381061865661 has 2 divisors, whose sum is σ = 1381061865662. Its totient is φ = 1381061865660.

The previous prime is 1381061865583. The next prime is 1381061865671. The reversal of 1381061865661 is 1665681601831.

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., 1163336973561 + 217724892100 = 1078581^2 + 466610^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1381061865661 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1381061865599 and 1381061865608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1381061865671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 690530932830 + 690530932831.

It is an arithmetic number, because the mean of its divisors is an integer number (690530932831).

Almost surely, 2^{1381061865661} is an apocalyptic number.

It is an amenable number.

1381061865661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1381061865661 is an equidigital number, since it uses as much as digits as its factorization.

1381061865661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1244160, while the sum is 52.

The spelling of 1381061865661 in words is "one trillion, three hundred eighty-one billion, sixty-one million, eight hundred sixty-five thousand, six hundred sixty-one".