1265971840 has 256 divisors, whose sum is σ = 3623040000. Its totient is φ = 422682624.

The previous prime is 1265971823. The next prime is 1265971853. The reversal of 1265971840 is 481795621.

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 31 ways as a sum of consecutive naturals, for example, 16024921 + ... + 16024999.

It is an arithmetic number, because the mean of its divisors is an integer number (14152500).

Almost surely, 2^1265971840 is an apocalyptic number.

1265971840 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 1265971840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1811520000).

1265971840 is an abundant number, since it is smaller than the sum of its proper divisors (2357068160).

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

1265971840 is an frugal number, since it uses more digits than its factorization.

1265971840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192 (or 166 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 43.

The square root of 1265971840 is about 35580.4980291170. The cubic root of 1265971840 is about 1081.7859795385.

The spelling of 1265971840 in words is "one billion, two hundred sixty-five million, nine hundred seventy-one thousand, eight hundred forty".