1287779631840 has 768 divisors, whose sum is σ = 5185956787200. Its totient is φ = 295809490944.

The previous prime is 1287779631823. The next prime is 1287779631869. The reversal of 1287779631840 is 481369777821.

1287779631840 is a `hidden beast` number, since 128 + 7 + 77 + 96 + 318 + 40 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 71482674 + ... + 71500686.

It is an arithmetic number, because the mean of its divisors is an integer number (6752547900).

Almost surely, 2^{1287779631840} is an apocalyptic number.

1287779631840 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 1287779631840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2592978393600).

1287779631840 is an abundant number, since it is smaller than the sum of its proper divisors (3898177155360).

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

1287779631840 is a wasteful number, since it uses less digits than its factorization.

1287779631840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18136 (or 18122 counting only the distinct ones).

The product of its (nonzero) digits is 28449792, while the sum is 63.

The spelling of 1287779631840 in words is "one trillion, two hundred eighty-seven billion, seven hundred seventy-nine million, six hundred thirty-one thousand, eight hundred forty".