21201210 has 128 divisors (see below), whose sum is σ = 62208000. Its totient is φ = 5114880.

The previous prime is 21201209. The next prime is 21201251. The reversal of 21201210 is 1210212.

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

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21201192 and 21201201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 142216 + ... + 142364.

It is an arithmetic number, because the mean of its divisors is an integer number (486000).

Almost surely, 2^21201210 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21201210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31104000).

21201210 is an abundant number, since it is smaller than the sum of its proper divisors (41006790).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21201210 is a wasteful number, since it uses less digits than its factorization.

21201210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213 (or 207 counting only the distinct ones).

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

The square root of 21201210 is about 4604.4771690171. The cubic root of 21201210 is about 276.7707661359.

Adding to 21201210 its reverse (1210212), we get a palindrome (22411422).

The spelling of 21201210 in words is "twenty-one million, two hundred one thousand, two hundred ten".