1265840000 has 80 divisors (see below), whose sum is σ = 3151428720. Its totient is φ = 506304000.

The previous prime is 1265839987. The next prime is 1265840003. The reversal of 1265840000 is 485621.

It is a tau number, because it is divible by the number of its divisors (80).

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1265840003) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 72089 + ... + 87911.

It is an arithmetic number, because the mean of its divisors is an integer number (39392859).

Almost surely, 2^1265840000 is an apocalyptic number.

1265840000 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 1265840000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1575714360).

1265840000 is an abundant number, since it is smaller than the sum of its proper divisors (1885588720).

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

1265840000 is an frugal number, since it uses more digits than its factorization.

1265840000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15857 (or 15830 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 1265840000 is about 35578.6452805612. The cubic root of 1265840000 is about 1081.7484253554.

The spelling of 1265840000 in words is "one billion, two hundred sixty-five million, eight hundred forty thousand".