1266599557440 has 1792 divisors, whose sum is σ = 5702344704000. Its totient is φ = 263363788800.

The previous prime is 1266599557439. The next prime is 1266599557511. The reversal of 1266599557440 is 447559956621.

1266599557440 is a `hidden beast` number, since 1 + 2 + 6 + 6 + 59 + 9 + 5 + 574 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 1561774635 + ... + 1561775445.

It is an arithmetic number, because the mean of its divisors is an integer number (3182112000).

Almost surely, 2^{1266599557440} is an apocalyptic number.

1266599557440 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 1266599557440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2851172352000).

1266599557440 is an abundant number, since it is smaller than the sum of its proper divisors (4435745146560).

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

1266599557440 is a wasteful number, since it uses less digits than its factorization.

1266599557440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 906 (or 876 counting only the distinct ones).

The product of its (nonzero) digits is 81648000, while the sum is 63.

The spelling of 1266599557440 in words is "one trillion, two hundred sixty-six billion, five hundred ninety-nine million, five hundred fifty-seven thousand, four hundred forty".