1265516644 has 24 divisors (see below), whose sum is σ = 2538103680. Its totient is φ = 540849216.

The previous prime is 1265516591. The next prime is 1265516653. The reversal of 1265516644 is 4466155621.

It is a junction number, because it is equal to n+sod(n) for n = 1265516597 and 1265516606.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 52897 + ... + 73000.

It is an arithmetic number, because the mean of its divisors is an integer number (105754320).

Almost surely, 2^1265516644 is an apocalyptic number.

1265516644 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

1265516644 is an abundant number, since it is smaller than the sum of its proper divisors (1272587036).

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

1265516644 is a wasteful number, since it uses less digits than its factorization.

1265516644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126267 (or 126265 counting only the distinct ones).

The product of its digits is 172800, while the sum is 40.

The square root of 1265516644 is about 35574.1007475944. The cubic root of 1265516644 is about 1081.6563074383.

The spelling of 1265516644 in words is "one billion, two hundred sixty-five million, five hundred sixteen thousand, six hundred forty-four".