1278117840 has 160 divisors (see below), whose sum is σ = 4205445120. Its totient is φ = 320205312.

The previous prime is 1278117809. The next prime is 1278117847. The reversal of 1278117840 is 487118721.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1278117847) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 578017 + ... + 580223.

It is an arithmetic number, because the mean of its divisors is an integer number (26284032).

Almost surely, 2^1278117840 is an apocalyptic number.

1278117840 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 1278117840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2102722560).

1278117840 is an abundant number, since it is smaller than the sum of its proper divisors (2927327280).

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

1278117840 is a wasteful number, since it uses less digits than its factorization.

1278117840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2369 (or 2363 counting only the distinct ones).

The product of its (nonzero) digits is 25088, while the sum is 39.

The square root of 1278117840 is about 35750.7739776358. The cubic root of 1278117840 is about 1085.2346013829.

The spelling of 1278117840 in words is "one billion, two hundred seventy-eight million, one hundred seventeen thousand, eight hundred forty".