21264210 has 96 divisors (see below), whose sum is σ = 61731072. Its totient is φ = 5034240.

The previous prime is 21264209. The next prime is 21264223. The reversal of 21264210 is 1246212.

21264210 is a `hidden beast` number, since 2 + 12 + 642 + 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 47 ways as a sum of consecutive naturals, for example, 46302 + ... + 46758.

It is an arithmetic number, because the mean of its divisors is an integer number (643032).

Almost surely, 2^21264210 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21264210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30865536).

21264210 is an abundant number, since it is smaller than the sum of its proper divisors (40466862).

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

21264210 is a wasteful number, since it uses less digits than its factorization.

21264210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528 (or 525 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21264210 is about 4611.3132619678. The cubic root of 21264210 is about 277.0446391152.

It can be divided in two parts, 2126 and 4210, that added together give a palindrome (6336).

The spelling of 21264210 in words is "twenty-one million, two hundred sixty-four thousand, two hundred ten".