21004201 has 4 divisors (see below), whose sum is σ = 21023572. Its totient is φ = 20984832.

The previous prime is 21004189. The next prime is 21004211. The reversal of 21004201 is 10240012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10732176 + 10272025 = 3276^2 + 3205^2 .

It is a cyclic number.

It is not a de Polignac number, because 21004201 - 2⁵ = 21004169 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21004211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7956 + ... + 10261.

It is an arithmetic number, because the mean of its divisors is an integer number (5255893).

Almost surely, 2^21004201 is an apocalyptic number.

It is an amenable number.

21004201 is a deficient number, since it is larger than the sum of its proper divisors (19371).

21004201 is a wasteful number, since it uses less digits than its factorization.

21004201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19370.

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 21004201 is about 4583.0340387128. The cubic root of 21004201 is about 275.9108136186.

Adding to 21004201 its reverse (10240012), we get a palindrome (31244213).

It can be divided in two parts, 2100 and 4201, that multiplied together give a triangular number (8822100 = T₄₂₀₀).

The spelling of 21004201 in words is "twenty-one million, four thousand, two hundred one".