1265556564 has 72 divisors (see below), whose sum is σ = 3285041760. Its totient is φ = 410582592.

The previous prime is 1265556559. The next prime is 1265556581. The reversal of 1265556564 is 4656555621.

1265556564 is a `hidden beast` number, since 1 + 26 + 5 + 5 + 565 + 64 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 489427 + ... + 492005.

It is an arithmetic number, because the mean of its divisors is an integer number (45625580).

Almost surely, 2^1265556564 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1265556564, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1642520880).

1265556564 is an abundant number, since it is smaller than the sum of its proper divisors (2019485196).

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

1265556564 is a wasteful number, since it uses less digits than its factorization.

1265556564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2949 (or 2944 counting only the distinct ones).

The product of its digits is 1080000, while the sum is 45.

The square root of 1265556564 is about 35574.6618255185. The cubic root of 1265556564 is about 1081.6676807289.

The spelling of 1265556564 in words is "one billion, two hundred sixty-five million, five hundred fifty-six thousand, five hundred sixty-four".