1366978541381 has 4 divisors (see below), whose sum is σ = 1367194944492. Its totient is φ = 1366762138272.

The previous prime is 1366978541377. The next prime is 1366978541387. The reversal of 1366978541381 is 1831458796631.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1082777600356 + 284200941025 = 1040566^2 + 533105^2 .

It is a cyclic number.

It is not a de Polignac number, because 1366978541381 - 2² = 1366978541377 is a prime.

It is a super-2 number, since 2×1366978541381² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1366978541387) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 108192080 + ... + 108204713.

It is an arithmetic number, because the mean of its divisors is an integer number (341798736123).

Almost surely, 2^{1366978541381} is an apocalyptic number.

It is an amenable number.

1366978541381 is a deficient number, since it is larger than the sum of its proper divisors (216403111).

1366978541381 is an equidigital number, since it uses as much as digits as its factorization.

1366978541381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216403110.

The product of its digits is 26127360, while the sum is 62.

The spelling of 1366978541381 in words is "one trillion, three hundred sixty-six billion, nine hundred seventy-eight million, five hundred forty-one thousand, three hundred eighty-one".