21262230 has 64 divisors (see below), whose sum is σ = 61862400. Its totient is φ = 5153760.

The previous prime is 21262229. The next prime is 21262237. The reversal of 21262230 is 3226212.

21262230 is a `hidden beast` number, since 2 + 12 + 622 + 30 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21262237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 610 + ... + 6549.

It is an arithmetic number, because the mean of its divisors is an integer number (966600).

Almost surely, 2^21262230 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21262230, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30931200).

21262230 is an abundant number, since it is smaller than the sum of its proper divisors (40600170).

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

21262230 is a wasteful number, since it uses less digits than its factorization.

21262230 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7186 (or 7180 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 21262230 is about 4611.0985675867. The cubic root of 21262230 is about 277.0360399179.

Adding to 21262230 its reverse (3226212), we get a palindrome (24488442).

It can be divided in two parts, 2126 and 2230, that added together give a square (4356 = 66²).

The spelling of 21262230 in words is "twenty-one million, two hundred sixty-two thousand, two hundred thirty".