1266129720720 has 200 divisors, whose sum is σ = 4432084614144. Its totient is φ = 334975834368.

The previous prime is 1266129720703. The next prime is 1266129720733. The reversal of 1266129720720 is 270279216621.

1266129720720 is a `hidden beast` number, since 1 + 2 + 6 + 612 + 9 + 7 + 2 + 0 + 7 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

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 39 ways as a sum of consecutive naturals, for example, 53707 + ... + 1592213.

Almost surely, 2^{1266129720720} is an apocalyptic number.

1266129720720 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 1266129720720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2216042307072).

1266129720720 is an abundant number, since it is smaller than the sum of its proper divisors (3165954893424).

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

1266129720720 is a wasteful number, since it uses less digits than its factorization.

1266129720720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1538659 (or 1538644 counting only the distinct ones).

The product of its (nonzero) digits is 254016, while the sum is 45.

The spelling of 1266129720720 in words is "one trillion, two hundred sixty-six billion, one hundred twenty-nine million, seven hundred twenty thousand, seven hundred twenty".