21210201 has 16 divisors (see below), whose sum is σ = 31715200. Its totient is φ = 14008464.

The previous prime is 21210197. The next prime is 21210221. The reversal of 21210201 is 10201212.

It is not a de Polignac number, because 21210201 - 2² = 21210197 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21210221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 661 + ... + 6546.

It is an arithmetic number, because the mean of its divisors is an integer number (1982200).

Almost surely, 2^21210201 is an apocalyptic number.

It is an amenable number.

21210201 is a deficient number, since it is larger than the sum of its proper divisors (10504999).

21210201 is a wasteful number, since it uses less digits than its factorization.

21210201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7325 (or 7319 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 21210201 is about 4605.4533978752. The cubic root of 21210201 is about 276.8098848823.

Adding to 21210201 its reverse (10201212), we get a palindrome (31411413).

It can be divided in two parts, 212 and 10201, that multiplied together give a palindrome (2162612).

The spelling of 21210201 in words is "twenty-one million, two hundred ten thousand, two hundred one".