21201213 has 16 divisors (see below), whose sum is σ = 31148352. Its totient is φ = 12720000.

The previous prime is 21201209. The next prime is 21201251. The reversal of 21201213 is 31210212.

It is not a de Polignac number, because 21201213 - 2² = 21201209 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201203) 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, 153 + ... + 6513.

It is an arithmetic number, because the mean of its divisors is an integer number (1946772).

Almost surely, 2^21201213 is an apocalyptic number.

It is an amenable number.

21201213 is a deficient number, since it is larger than the sum of its proper divisors (9947139).

21201213 is a wasteful number, since it uses less digits than its factorization.

21201213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6476.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21201213 is about 4604.4774947870. The cubic root of 21201213 is about 276.7707791904.

Adding to 21201213 its reverse (31210212), we get a palindrome (52411425).

It can be divided in two parts, 2120 and 1213, that added together give a palindrome (3333).

The spelling of 21201213 in words is "twenty-one million, two hundred one thousand, two hundred thirteen".