21436530 has 16 divisors (see below), whose sum is σ = 51447744. Its totient is φ = 5716400.

The previous prime is 21436517. The next prime is 21436549. The reversal of 21436530 is 3563412.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21436530.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 357246 + ... + 357305.

It is an arithmetic number, because the mean of its divisors is an integer number (3215484).

Almost surely, 2^21436530 is an apocalyptic number.

21436530 is an abundant number, since it is smaller than the sum of its proper divisors (30011214).

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

21436530 is a wasteful number, since it uses less digits than its factorization.

21436530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 714561.

The product of its (nonzero) digits is 2160, while the sum is 24.

The square root of 21436530 is about 4629.9600430241. The cubic root of 21436530 is about 277.7909941564.

Adding to 21436530 its reverse (3563412), we get a palindrome (24999942).

The spelling of 21436530 in words is "twenty-one million, four hundred thirty-six thousand, five hundred thirty".