2778456681 has 128 divisors (see below), whose sum is σ = 5563514880. Its totient is φ = 1323475200.

The previous prime is 2778456671. The next prime is 2778456713. The reversal of 2778456681 is 1866548772.

2778456681 is a `hidden beast` number, since 2 + 7 + 78 + 4 + 566 + 8 + 1 = 666.

It is not a de Polignac number, because 2778456681 - 2¹¹ = 2778454633 is a prime.

It is a super-2 number, since 2×2778456681² = 15439643056387071522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2778456601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 6026791 + ... + 6027251.

It is an arithmetic number, because the mean of its divisors is an integer number (43464960).

Almost surely, 2^2778456681 is an apocalyptic number.

2778456681 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2778456681 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

2778456681 is a wasteful number, since it uses less digits than its factorization.

2778456681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 724 (or 718 counting only the distinct ones).

The product of its digits is 4515840, while the sum is 54.

The square root of 2778456681 is about 52711.0679174687. The cubic root of 2778456681 is about 1405.8356213384.

The spelling of 2778456681 in words is "two billion, seven hundred seventy-eight million, four hundred fifty-six thousand, six hundred eighty-one".