1278249984 has 264 divisors, whose sum is σ = 4184526528. Its totient is φ = 386519040.

The previous prime is 1278249971. The next prime is 1278250003. The reversal of 1278249984 is 4899428721.

1278249984 is a `hidden beast` number, since 1 + 2 + 78 + 2 + 499 + 84 = 666.

It is a tau number, because it is divible by the number of its divisors (264).

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 1278249984.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2736919 + ... + 2737385.

Almost surely, 2^1278249984 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1278249984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2092263264).

1278249984 is an abundant number, since it is smaller than the sum of its proper divisors (2906276544).

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

1278249984 is an equidigital number, since it uses as much as digits as its factorization.

1278249984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 513 (or 483 counting only the distinct ones).

The product of its digits is 2322432, while the sum is 54.

The square root of 1278249984 is about 35752.6220576897. The cubic root of 1278249984 is about 1085.2720007251.

The spelling of 1278249984 in words is "one billion, two hundred seventy-eight million, two hundred forty-nine thousand, nine hundred eighty-four".