1266380881920 has 720 divisors, whose sum is σ = 5473475175168. Its totient is φ = 263132282880.

The previous prime is 1266380881861. The next prime is 1266380881963. The reversal of 1266380881920 is 291880836621.

1266380881920 is a `hidden beast` number, since 12 + 66 + 380 + 8 + 8 + 192 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 56759407 + ... + 56781713.

Almost surely, 2^{1266380881920} is an apocalyptic number.

1266380881920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1266380881920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2736737587584).

1266380881920 is an abundant number, since it is smaller than the sum of its proper divisors (4207094293248).

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

1266380881920 is a wasteful number, since it uses less digits than its factorization.

1266380881920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22364 (or 22335 counting only the distinct ones).

The product of its (nonzero) digits is 1990656, while the sum is 54.

The spelling of 1266380881920 in words is "one trillion, two hundred sixty-six billion, three hundred eighty million, eight hundred eighty-one thousand, nine hundred twenty".