4189921 has 4 divisors (see below), whose sum is σ = 4202692. Its totient is φ = 4177152.

The previous prime is 4189903. The next prime is 4189951. The reversal of 4189921 is 1299814.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1299814 = 2 ⋅649907.

It can be written as a sum of positive squares in 2 ways, for example, as 819025 + 3370896 = 905^2 + 1836^2 .

It is a cyclic number.

It is not a de Polignac number, because 4189921 - 2⁷ = 4189793 is a prime.

It is a Duffinian number.

4189921 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4189951) 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, 5880 + ... + 6553.

It is an arithmetic number, because the mean of its divisors is an integer number (1050673).

Almost surely, 2^4189921 is an apocalyptic number.

It is an amenable number.

4189921 is a deficient number, since it is larger than the sum of its proper divisors (12771).

4189921 is a wasteful number, since it uses less digits than its factorization.

4189921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12770.

The product of its digits is 5184, while the sum is 34.

The square root of 4189921 is about 2046.9296519421. The cubic root of 4189921 is about 161.2136997390.

The spelling of 4189921 in words is "four million, one hundred eighty-nine thousand, nine hundred twenty-one".