1266243840 has 504 divisors, whose sum is σ = 4825638720. Its totient is φ = 317509632.

The previous prime is 1266243799. The next prime is 1266243841. The reversal of 1266243840 is 483426621.

1266243840 is a `hidden beast` number, since 1 + 26 + 624 + 3 + 8 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1266243795 and 1266243804.

It is not an unprimeable number, because it can be changed into a prime (1266243841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 21461731 + ... + 21461789.

It is an arithmetic number, because the mean of its divisors is an integer number (9574680).

Almost surely, 2^1266243840 is an apocalyptic number.

1266243840 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 1266243840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2412819360).

1266243840 is an abundant number, since it is smaller than the sum of its proper divisors (3559394880).

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

1266243840 is an frugal number, since it uses more digits than its factorization.

1266243840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121 (or 92 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

The square root of 1266243840 is about 35584.3201424448. The cubic root of 1266243840 is about 1081.8634495912.

The spelling of 1266243840 in words is "one billion, two hundred sixty-six million, two hundred forty-three thousand, eight hundred forty".