2778806 has 4 divisors (see below), whose sum is σ = 4168212. Its totient is φ = 1389402.

The previous prime is 2778799. The next prime is 2778823. The reversal of 2778806 is 6088772.

It is a semiprime because it is the product of two primes.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2778806.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 694700 + ... + 694703.

It is an arithmetic number, because the mean of its divisors is an integer number (1042053).

2^2778806 is an apocalyptic number.

2778806 is a deficient number, since it is larger than the sum of its proper divisors (1389406).

2778806 is a wasteful number, since it uses less digits than its factorization.

2778806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1389405.

The product of its (nonzero) digits is 37632, while the sum is 38.

The square root of 2778806 is about 1666.9751047931. The cubic root of 2778806 is about 140.5894534681.

The spelling of 2778806 in words is "two million, seven hundred seventy-eight thousand, eight hundred six".