4121821 has 8 divisors (see below), whose sum is σ = 4544064. Its totient is φ = 3707520.

The previous prime is 4121809. The next prime is 4121827. The reversal of 4121821 is 1281214.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 4121821 - 2⁷ = 4121693 is a prime.

It is a Duffinian number.

4121821 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4121827) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 865 + ... + 2998.

It is an arithmetic number, because the mean of its divisors is an integer number (568008).

Almost surely, 2^4121821 is an apocalyptic number.

It is an amenable number.

4121821 is a deficient number, since it is larger than the sum of its proper divisors (422243).

4121821 is a wasteful number, since it uses less digits than its factorization.

4121821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3971.

The product of its digits is 128, while the sum is 19.

The square root of 4121821 is about 2030.2268346173. The cubic root of 4121821 is about 160.3355069152.

The spelling of 4121821 in words is "four million, one hundred twenty-one thousand, eight hundred twenty-one".