1376666381 has 2 divisors, whose sum is σ = 1376666382. Its totient is φ = 1376666380.

The previous prime is 1376666327. The next prime is 1376666393. The reversal of 1376666381 is 1836666731.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1151516356 + 225150025 = 33934^2 + 15005^2 .

It is an emirp because it is prime and its reverse (1836666731) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1376666381 - 2¹⁰ = 1376665357 is a prime.

It is a super-3 number, since 3×1376666381³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1376666581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 688333190 + 688333191.

It is an arithmetic number, because the mean of its divisors is an integer number (688333191).

Almost surely, 2^1376666381 is an apocalyptic number.

It is an amenable number.

1376666381 is a deficient number, since it is larger than the sum of its proper divisors (1).

1376666381 is an equidigital number, since it uses as much as digits as its factorization.

1376666381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 653184, while the sum is 47.

The square root of 1376666381 is about 37103.4551086553. The cubic root of 1376666381 is about 1112.4390758372.

The spelling of 1376666381 in words is "one billion, three hundred seventy-six million, six hundred sixty-six thousand, three hundred eighty-one".