2178891 has 24 divisors (see below), whose sum is σ = 3699696. Its totient is φ = 1218240.

The previous prime is 2178889. The next prime is 2178937. The reversal of 2178891 is 1988712.

It is not a de Polignac number, because 2178891 - 2¹ = 2178889 is a prime.

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 23 ways as a sum of consecutive naturals, for example, 441 + ... + 2133.

It is an arithmetic number, because the mean of its divisors is an integer number (154154).

2^2178891 is an apocalyptic number.

2178891 is a deficient number, since it is larger than the sum of its proper divisors (1520805).

2178891 is a wasteful number, since it uses less digits than its factorization.

2178891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1723 (or 1720 counting only the distinct ones).

The product of its digits is 8064, while the sum is 36.

The square root of 2178891 is about 1476.1067034602. The cubic root of 2178891 is about 129.6418346311.

The spelling of 2178891 in words is "two million, one hundred seventy-eight thousand, eight hundred ninety-one".