21432210 has 32 divisors (see below), whose sum is σ = 51734592. Its totient is φ = 5682240.

The previous prime is 21432199. The next prime is 21432211. The reversal of 21432210 is 1223412.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21432210.

It is not an unprimeable number, because it can be changed into a prime (21432211) 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, 3457 + ... + 7403.

It is an arithmetic number, because the mean of its divisors is an integer number (1616706).

Almost surely, 2^21432210 is an apocalyptic number.

21432210 is an abundant number, since it is smaller than the sum of its proper divisors (30302382).

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

21432210 is a wasteful number, since it uses less digits than its factorization.

21432210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4138.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21432210 is about 4629.4934928132. The cubic root of 21432210 is about 277.7723322784.

Adding to 21432210 its reverse (1223412), we get a palindrome (22655622).

The spelling of 21432210 in words is "twenty-one million, four hundred thirty-two thousand, two hundred ten".