21363210 has 64 divisors (see below), whose sum is σ = 62156160. Its totient is φ = 5178240.

The previous prime is 21363193. The next prime is 21363253. The reversal of 21363210 is 1236312.

21363210 is a `hidden beast` number, since 21 + 3 + 632 + 10 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 627 + ... + 6566.

It is an arithmetic number, because the mean of its divisors is an integer number (971190).

Almost surely, 2^21363210 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21363210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31078080).

21363210 is an abundant number, since it is smaller than the sum of its proper divisors (40792950).

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

21363210 is a wasteful number, since it uses less digits than its factorization.

21363210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7220 (or 7214 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 21363210 is about 4622.0352659840. The cubic root of 21363210 is about 277.4739201203.

Adding to 21363210 its reverse (1236312), we get a palindrome (22599522).

The spelling of 21363210 in words is "twenty-one million, three hundred sixty-three thousand, two hundred ten".