4201821 has 16 divisors (see below), whose sum is σ = 6704320. Its totient is φ = 2585520.

The previous prime is 4201817. The next prime is 4201837. The reversal of 4201821 is 1281024.

It is not a de Polignac number, because 4201821 - 2² = 4201817 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 4201794 and 4201803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4201811) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5635 + ... + 6336.

It is an arithmetic number, because the mean of its divisors is an integer number (419020).

Almost surely, 2^4201821 is an apocalyptic number.

It is an amenable number.

4201821 is a deficient number, since it is larger than the sum of its proper divisors (2502499).

4201821 is a wasteful number, since it uses less digits than its factorization.

4201821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11993 (or 11987 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 4201821 is about 2049.8343835539. The cubic root of 4201821 is about 161.3661791187.

Adding to 4201821 its reverse (1281024), we get a palindrome (5482845).

The spelling of 4201821 in words is "four million, two hundred one thousand, eight hundred twenty-one".