1265881440 has 48 divisors (see below), whose sum is σ = 3987528048. Its totient is φ = 337568256.

The previous prime is 1265881411. The next prime is 1265881499. The reversal of 1265881440 is 441885621.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1318147 + ... + 1319106.

It is an arithmetic number, because the mean of its divisors is an integer number (83073501).

Almost surely, 2^1265881440 is an apocalyptic number.

1265881440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1265881440 is an abundant number, since it is smaller than the sum of its proper divisors (2721646608).

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

1265881440 is a wasteful number, since it uses less digits than its factorization.

1265881440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2637271 (or 2637263 counting only the distinct ones).

The product of its (nonzero) digits is 61440, while the sum is 39.

The square root of 1265881440 is about 35579.2276476036. The cubic root of 1265881440 is about 1081.7602296818.

The spelling of 1265881440 in words is "one billion, two hundred sixty-five million, eight hundred eighty-one thousand, four hundred forty".