1266817780900 has 135 divisors (see below), whose sum is σ = 3208366289219. Its totient is φ = 434148435840.

The previous prime is 1266817780897. The next prime is 1266817780909. The reversal of 1266817780900 is 90877186621.

The square root of 1266817780900 is 1125530.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 37007755876 + 1229810025024 = 192374^2 + 1108968^2 .

It is not an unprimeable number, because it can be changed into a prime (1266817780909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 551508552 + ... + 551510848.

Almost surely, 2^{1266817780900} is an apocalyptic number.

1266817780900 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1266817780900 is the 1125530-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1266817780900

1266817780900 is an abundant number, since it is smaller than the sum of its proper divisors (1941548508319).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1266817780900 is an frugal number, since it uses more digits than its factorization.

1266817780900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4636 (or 2311 counting only the distinct ones).

The product of its (nonzero) digits is 2032128, while the sum is 55.

The spelling of 1266817780900 in words is "one trillion, two hundred sixty-six billion, eight hundred seventeen million, seven hundred eighty thousand, nine hundred".