1266555550999 has 2 divisors, whose sum is σ = 1266555551000. Its totient is φ = 1266555550998.

The previous prime is 1266555550979. The next prime is 1266555551011. The reversal of 1266555550999 is 9990555556621.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1266555550999 - 2¹³ = 1266555542807 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1266555550979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 633277775499 + 633277775500.

It is an arithmetic number, because the mean of its divisors is an integer number (633277775500).

Almost surely, 2^{1266555550999} is an apocalyptic number.

1266555550999 is a deficient number, since it is larger than the sum of its proper divisors (1).

1266555550999 is an equidigital number, since it uses as much as digits as its factorization.

1266555550999 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 164025000, while the sum is 67.

The spelling of 1266555550999 in words is "one trillion, two hundred sixty-six billion, five hundred fifty-five million, five hundred fifty thousand, nine hundred ninety-nine".