21009201 has 8 divisors (see below), whose sum is σ = 28035744. Its totient is φ = 13994400.

The previous prime is 21009199. The next prime is 21009211. The reversal of 21009201 is 10290012.

It is a happy number.

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

It is not a de Polignac number, because 21009201 - 2¹ = 21009199 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21009211) 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, 2901 + ... + 7101.

It is an arithmetic number, because the mean of its divisors is an integer number (3504468).

Almost surely, 2^21009201 is an apocalyptic number.

It is an amenable number.

21009201 is a deficient number, since it is larger than the sum of its proper divisors (7026543).

21009201 is a wasteful number, since it uses less digits than its factorization.

21009201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5871.

The product of its (nonzero) digits is 36, while the sum is 15.

The square root of 21009201 is about 4583.5794964198. The cubic root of 21009201 is about 275.9327051855.

Adding to 21009201 its reverse (10290012), we get a palindrome (31299213).

The spelling of 21009201 in words is "twenty-one million, nine thousand, two hundred one".