2189921 has 4 divisors (see below), whose sum is σ = 2305200. Its totient is φ = 2074644.

The previous prime is 2189881. The next prime is 2189939. The reversal of 2189921 is 1299812.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2189921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2189981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57611 + ... + 57648.

It is an arithmetic number, because the mean of its divisors is an integer number (576300).

2^2189921 is an apocalyptic number.

It is an amenable number.

2189921 is a deficient number, since it is larger than the sum of its proper divisors (115279).

2189921 is a wasteful number, since it uses less digits than its factorization.

2189921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115278.

The product of its digits is 2592, while the sum is 32.

The square root of 2189921 is about 1479.8381668277. The cubic root of 2189921 is about 129.8602245213.

The spelling of 2189921 in words is "two million, one hundred eighty-nine thousand, nine hundred twenty-one".