2778238680 has 128 divisors (see below), whose sum is σ = 9564065280. Its totient is φ = 632448000.

The previous prime is 2778238637. The next prime is 2778238703. The reversal of 2778238680 is 868328772.

It is a Cunningham number, because it is equal to 52709²-1.

It is a super-2 number, since 2×2778238680² = 15437220326096284800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 204252 + ... + 217428.

It is an arithmetic number, because the mean of its divisors is an integer number (74719260).

Almost surely, 2^2778238680 is an apocalyptic number.

2778238680 is a gapful number since it is divisible by the number (20) 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 2778238680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4782032640).

2778238680 is an abundant number, since it is smaller than the sum of its proper divisors (6785826600).

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

2778238680 is a wasteful number, since it uses less digits than its factorization.

2778238680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13449 (or 13445 counting only the distinct ones).

The product of its (nonzero) digits is 1806336, while the sum is 51.

The square root of 2778238680 is about 52708.9999905140. Note that the first 5 decimals coincide. The cubic root of 2778238680 is about 1405.7988525345.

The spelling of 2778238680 in words is "two billion, seven hundred seventy-eight million, two hundred thirty-eight thousand, six hundred eighty".