1265381680 has 40 divisors (see below), whose sum is σ = 2947271184. Its totient is φ = 505248000.

The previous prime is 1265381671. The next prime is 1265381681. The reversal of 1265381680 is 861835621.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (1265381681) by changing a digit.

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, 31830 + ... + 59530.

Almost surely, 2^1265381680 is an apocalyptic number.

1265381680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1265381680 is an abundant number, since it is smaller than the sum of its proper divisors (1681889504).

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

1265381680 is a wasteful number, since it uses less digits than its factorization.

1265381680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28285 (or 28279 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 40.

The square root of 1265381680 is about 35572.2037551794. The cubic root of 1265381680 is about 1081.6178541440.

The spelling of 1265381680 in words is "one billion, two hundred sixty-five million, three hundred eighty-one thousand, six hundred eighty".