4200821 has 2 divisors, whose sum is σ = 4200822. Its totient is φ = 4200820.

The previous prime is 4200809. The next prime is 4200827. The reversal of 4200821 is 1280024.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3496900 + 703921 = 1870^2 + 839^2 .

It is a cyclic number.

It is not a de Polignac number, because 4200821 - 2¹⁴ = 4184437 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 4200821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4200827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2100410 + 2100411.

It is an arithmetic number, because the mean of its divisors is an integer number (2100411).

Almost surely, 2^4200821 is an apocalyptic number.

It is an amenable number.

4200821 is a deficient number, since it is larger than the sum of its proper divisors (1).

4200821 is an equidigital number, since it uses as much as digits as its factorization.

4200821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 4200821 is about 2049.5904468942. The cubic root of 4200821 is about 161.3533768137.

Adding to 4200821 its reverse (1280024), we get a palindrome (5480845).

The spelling of 4200821 in words is "four million, two hundred thousand, eight hundred twenty-one".