1266426340639 has 4 divisors (see below), whose sum is σ = 1271861647056. Its totient is φ = 1260991034224.

The previous prime is 1266426340589. The next prime is 1266426340681. The reversal of 1266426340639 is 9360436246621.

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

It is a cyclic number.

It is not a de Polignac number, because 1266426340639 - 2¹⁷ = 1266426209567 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1266466340639) 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, 2717652859 + ... + 2717653324.

It is an arithmetic number, because the mean of its divisors is an integer number (317965411764).

Almost surely, 2^{1266426340639} is an apocalyptic number.

1266426340639 is a deficient number, since it is larger than the sum of its proper divisors (5435306417).

1266426340639 is an equidigital number, since it uses as much as digits as its factorization.

1266426340639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5435306416.

The product of its (nonzero) digits is 6718464, while the sum is 52.

The spelling of 1266426340639 in words is "one trillion, two hundred sixty-six billion, four hundred twenty-six million, three hundred forty thousand, six hundred thirty-nine".