2155778 has 8 divisors (see below), whose sum is σ = 3403920. Its totient is φ = 1021140.

The previous prime is 2155733. The next prime is 2155781. The reversal of 2155778 is 8775512.

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 (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28328 + ... + 28403.

It is an arithmetic number, because the mean of its divisors is an integer number (425490).

2^2155778 is an apocalyptic number.

2155778 is a deficient number, since it is larger than the sum of its proper divisors (1248142).

2155778 is a wasteful number, since it uses less digits than its factorization.

2155778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56752.

The product of its digits is 19600, while the sum is 35.

The square root of 2155778 is about 1468.2567895297. The cubic root of 2155778 is about 129.1818040301.

The spelling of 2155778 in words is "two million, one hundred fifty-five thousand, seven hundred seventy-eight".