21135524 has 48 divisors (see below), whose sum is σ = 40830720. Its totient is φ = 9538560.

The previous prime is 21135503. The next prime is 21135553. The reversal of 21135524 is 42553112.

It is a self number, because there is not a number n which added to its sum of digits gives 21135524.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 217844 + ... + 217940.

It is an arithmetic number, because the mean of its divisors is an integer number (850640).

Almost surely, 2^21135524 is an apocalyptic number.

It is an amenable number.

21135524 is a deficient number, since it is larger than the sum of its proper divisors (19695196).

21135524 is a wasteful number, since it uses less digits than its factorization.

21135524 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 228 (or 226 counting only the distinct ones).

The product of its digits is 1200, while the sum is 23.

The square root of 21135524 is about 4597.3387954337. The cubic root of 21135524 is about 276.4846382514.

Adding to 21135524 its reverse (42553112), we get a palindrome (63688636).

The spelling of 21135524 in words is "twenty-one million, one hundred thirty-five thousand, five hundred twenty-four".