2178091 has 8 divisors (see below), whose sum is σ = 2381184. Its totient is φ = 1983360.

The previous prime is 2178083. The next prime is 2178131. The reversal of 2178091 is 1908712.

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

It is a cyclic number.

It is not a de Polignac number, because 2178091 - 2³ = 2178083 is a prime.

It is an Ulam number.

It is a Duffinian number.

2178091 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2178191) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1540 + ... + 2593.

It is an arithmetic number, because the mean of its divisors is an integer number (297648).

2^2178091 is an apocalyptic number.

2178091 is a deficient number, since it is larger than the sum of its proper divisors (203093).

2178091 is a wasteful number, since it uses less digits than its factorization.

2178091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4181.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 2178091 is about 1475.8356954621. The cubic root of 2178091 is about 129.6259662890.

The spelling of 2178091 in words is "two million, one hundred seventy-eight thousand, ninety-one".