1278224640 has 648 divisors, whose sum is σ = 5597976384. Its totient is φ = 263577600.

The previous prime is 1278224621. The next prime is 1278224641. The reversal of 1278224640 is 464228721.

1278224640 is a `hidden beast` number, since 1 + 2 + 7 + 8 + 2 + 2 + 4 + 640 = 666.

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 = 1278224595 and 1278224604.

It is not an unprimeable number, because it can be changed into a prime (1278224641) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 9757375 + ... + 9757505.

Almost surely, 2^1278224640 is an apocalyptic number.

1278224640 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 1278224640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2798988192).

1278224640 is an abundant number, since it is smaller than the sum of its proper divisors (4319751744).

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

1278224640 is a wasteful number, since it uses less digits than its factorization.

1278224640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187 (or 159 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 36.

The square root of 1278224640 is about 35752.2676203902. The cubic root of 1278224640 is about 1085.2648280761.

The spelling of 1278224640 in words is "one billion, two hundred seventy-eight million, two hundred twenty-four thousand, six hundred forty".