1265538681940 has 24 divisors (see below), whose sum is σ = 2862064404360. Its totient is φ = 467275820928.

The previous prime is 1265538681887. The next prime is 1265538681941. The reversal of 1265538681940 is 491868355621.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 87245799876 + 1178292882064 = 295374^2 + 1085492^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1265538681941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2433727975 + ... + 2433728494.

It is an arithmetic number, because the mean of its divisors is an integer number (119252683515).

Almost surely, 2^{1265538681940} is an apocalyptic number.

1265538681940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1265538681940 is an abundant number, since it is smaller than the sum of its proper divisors (1596525722420).

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

1265538681940 is a wasteful number, since it uses less digits than its factorization.

1265538681940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4867456491 (or 4867456489 counting only the distinct ones).

The product of its (nonzero) digits is 12441600, while the sum is 58.

The spelling of 1265538681940 in words is "one trillion, two hundred sixty-five billion, five hundred thirty-eight million, six hundred eighty-one thousand, nine hundred forty".