1266155520 has 320 divisors, whose sum is σ = 4831833600. Its totient is φ = 276824064.

The previous prime is 1266155441. The next prime is 1266155551. The reversal of 1266155520 is 255516621.

It is a tau number, because it is divible by the number of its divisors (320).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55050229 + ... + 55050251.

It is an arithmetic number, because the mean of its divisors is an integer number (15099480).

Almost surely, 2^1266155520 is an apocalyptic number.

1266155520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1266155520 is a droll number since its even prime factors and its odd prime factors have the same sum.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1266155520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2415916800).

1266155520 is an abundant number, since it is smaller than the sum of its proper divisors (3565678080).

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

1266155520 is an frugal number, since it uses more digits than its factorization.

1266155520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76 (or 40 counting only the distinct ones).

The product of its (nonzero) digits is 18000, while the sum is 33.

The square root of 1266155520 is about 35583.0791247750. The cubic root of 1266155520 is about 1081.8382958258.

The spelling of 1266155520 in words is "one billion, two hundred sixty-six million, one hundred fifty-five thousand, five hundred twenty".