21352556 has 18 divisors (see below), whose sum is σ = 39066132. Its totient is φ = 10211080.

The previous prime is 21352549. The next prime is 21352559. The reversal of 21352556 is 65525312.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21352559) 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 5 ways as a sum of consecutive naturals, for example, 2930 + ... + 7161.

Almost surely, 2^21352556 is an apocalyptic number.

It is an amenable number.

21352556 is a deficient number, since it is larger than the sum of its proper divisors (17713576).

21352556 is a wasteful number, since it uses less digits than its factorization.

21352556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10141 (or 10116 counting only the distinct ones).

The product of its digits is 9000, while the sum is 29.

The square root of 21352556 is about 4620.8825996773. The cubic root of 21352556 is about 277.4277863119.

Adding to 21352556 its reverse (65525312), we get a palindrome (86877868).

The spelling of 21352556 in words is "twenty-one million, three hundred fifty-two thousand, five hundred fifty-six".