1265918940 has 432 divisors, whose sum is σ = 4831130304. Its totient is φ = 265605120.

The previous prime is 1265918921. The next prime is 1265918963. The reversal of 1265918940 is 498195621.

1265918940 is a `hidden beast` number, since 12 + 6 + 591 + 8 + 9 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 4813249 + ... + 4813511.

It is an arithmetic number, because the mean of its divisors is an integer number (11183172).

Almost surely, 2^1265918940 is an apocalyptic number.

1265918940 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 1265918940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2415565152).

1265918940 is an abundant number, since it is smaller than the sum of its proper divisors (3565211364).

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

1265918940 is a wasteful number, since it uses less digits than its factorization.

1265918940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330 (or 314 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The square root of 1265918940 is about 35579.7546365907. The cubic root of 1265918940 is about 1081.7709114636.

It can be divided in two parts, 126591 and 8940, that added together give a palindrome (135531).

The spelling of 1265918940 in words is "one billion, two hundred sixty-five million, nine hundred eighteen thousand, nine hundred forty".