2188921 has 4 divisors (see below), whose sum is σ = 2501632. Its totient is φ = 1876212.

The previous prime is 2188919. The next prime is 2188981. The reversal of 2188921 is 1298812.

It is a happy number.

2188921 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 Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2188921 - 2¹ = 2188919 is a prime.

It is the 1480-th Hogben number.

It is not an unprimeable number, because it can be changed into a prime (2188981) by changing a digit.

It is a nontrivial repunit in base 1479.

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, 156345 + ... + 156358.

It is an arithmetic number, because the mean of its divisors is an integer number (625408).

2^2188921 is an apocalyptic number.

It is an amenable number.

2188921 is a deficient number, since it is larger than the sum of its proper divisors (312711).

2188921 is an equidigital number, since it uses as much as digits as its factorization.

2188921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312710.

The product of its digits is 2304, while the sum is 31.

The square root of 2188921 is about 1479.5002534640. The cubic root of 2188921 is about 129.8404551634.

The spelling of 2188921 in words is "two million, one hundred eighty-eight thousand, nine hundred twenty-one".