1278422640 has 480 divisors, whose sum is σ = 4991680512. Its totient is φ = 290304000.

The previous prime is 1278422623. The next prime is 1278422659. The reversal of 1278422640 is 462248721.

1278422640 is a `hidden beast` number, since 1 + 2 + 7 + 8 + 4 + 2 + 2 + 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 = 1278422595 and 1278422604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 10066257 + ... + 10066383.

Almost surely, 2^1278422640 is an apocalyptic number.

1278422640 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 1278422640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2495840256).

1278422640 is an abundant number, since it is smaller than the sum of its proper divisors (3713257872).

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

1278422640 is a wasteful number, since it uses less digits than its factorization.

1278422640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229 (or 220 counting only the distinct ones).

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

The square root of 1278422640 is about 35755.0365682934. The cubic root of 1278422640 is about 1085.3208618735.

The spelling of 1278422640 in words is "one billion, two hundred seventy-eight million, four hundred twenty-two thousand, six hundred forty".