1266386623657 has 4 divisors (see below), whose sum is σ = 1266392088720. Its totient is φ = 1266381158596.

The previous prime is 1266386623639. The next prime is 1266386623681. The reversal of 1266386623657 is 7563266836621.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1266386623657 - 2³¹ = 1264239140009 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1266386623595 and 1266386623604.

It is not an unprimeable number, because it can be changed into a prime (1266386623687) 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, 2368807 + ... + 2853772.

It is an arithmetic number, because the mean of its divisors is an integer number (316598022180).

Almost surely, 2^{1266386623657} is an apocalyptic number.

It is an amenable number.

1266386623657 is a deficient number, since it is larger than the sum of its proper divisors (5465063).

1266386623657 is an equidigital number, since it uses as much as digits as its factorization.

1266386623657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5465062.

The product of its digits is 78382080, while the sum is 61.

The spelling of 1266386623657 in words is "one trillion, two hundred sixty-six billion, three hundred eighty-six million, six hundred twenty-three thousand, six hundred fifty-seven".