2778551978 has 8 divisors (see below), whose sum is σ = 4412994372. Its totient is φ = 1307553856.

The previous prime is 2778551957. The next prime is 2778551987. The reversal of 2778551978 is 8791558772.

It can be written as a sum of positive squares in 2 ways, for example, as 2492705329 + 285846649 = 49927^2 + 16907^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 40861025 + ... + 40861092.

Almost surely, 2^2778551978 is an apocalyptic number.

2778551978 is a deficient number, since it is larger than the sum of its proper divisors (1634442394).

2778551978 is a wasteful number, since it uses less digits than its factorization.

2778551978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81722136.

The product of its digits is 9878400, while the sum is 59.

The square root of 2778551978 is about 52711.9718659813. The cubic root of 2778551978 is about 1405.8516938565.

The spelling of 2778551978 in words is "two billion, seven hundred seventy-eight million, five hundred fifty-one thousand, nine hundred seventy-eight".