21100201 has 4 divisors (see below), whose sum is σ = 21498372. Its totient is φ = 20702032.

The previous prime is 21100193. The next prime is 21100207. The reversal of 21100201 is 10200112.

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 17842176 + 3258025 = 4224^2 + 1805^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100201 - 2³ = 21100193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21100207) 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, 199006 + ... + 199111.

It is an arithmetic number, because the mean of its divisors is an integer number (5374593).

Almost surely, 2^21100201 is an apocalyptic number.

It is an amenable number.

21100201 is a deficient number, since it is larger than the sum of its proper divisors (398171).

21100201 is an equidigital number, since it uses as much as digits as its factorization.

21100201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398170.

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 21100201 is about 4593.4955099575. The cubic root of 21100201 is about 276.3305262675.

Adding to 21100201 its reverse (10200112), we get a palindrome (31300313).

The spelling of 21100201 in words is "twenty-one million, one hundred thousand, two hundred one".