1296138240 has 256 divisors, whose sum is σ = 4624149600. Its totient is φ = 344457216.

The previous prime is 1296138229. The next prime is 1296138253. The reversal of 1296138240 is 428316921.

1296138240 is a `hidden beast` number, since 12 + 9 + 613 + 8 + 24 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (256).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1296138195 and 1296138204.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4423534 + ... + 4423826.

Almost surely, 2^1296138240 is an apocalyptic number.

1296138240 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 1296138240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2312074800).

1296138240 is an abundant number, since it is smaller than the sum of its proper divisors (3328011360).

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

1296138240 is an frugal number, since it uses more digits than its factorization.

1296138240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 337 (or 303 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 1296138240 is about 36001.9199488027. The cubic root of 1296138240 is about 1090.3111195604.

The spelling of 1296138240 in words is "one billion, two hundred ninety-six million, one hundred thirty-eight thousand, two hundred forty".