2178961 has 4 divisors (see below), whose sum is σ = 2181924. Its totient is φ = 2176000.

The previous prime is 2178947. The next prime is 2178983. The reversal of 2178961 is 1698712.

It is a happy number.

2178961 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 1488400 + 690561 = 1220^2 + 831^2 .

It is a cyclic number.

It is not a de Polignac number, because 2178961 - 2¹⁹ = 1654673 is a prime.

It is a Duffinian number.

2178961 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2178991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 561 + ... + 2161.

It is an arithmetic number, because the mean of its divisors is an integer number (545481).

2^2178961 is an apocalyptic number.

It is an amenable number.

2178961 is a deficient number, since it is larger than the sum of its proper divisors (2963).

2178961 is a wasteful number, since it uses less digits than its factorization.

2178961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2962.

The product of its digits is 6048, while the sum is 34.

The square root of 2178961 is about 1476.1304142927. The cubic root of 2178961 is about 129.6432229262.

Subtracting from 2178961 its reverse (1698712), we obtain a square (480249 = 693²).

The spelling of 2178961 in words is "two million, one hundred seventy-eight thousand, nine hundred sixty-one".