21343556 has 12 divisors (see below), whose sum is σ = 40224492. Its totient is φ = 9850848.

The previous prime is 21343519. The next prime is 21343579. The reversal of 21343556 is 65534312.

It can be written as a sum of positive squares in 2 ways, for example, as 2560000 + 18783556 = 1600^2 + 4334^2 .

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 205175 + ... + 205278.

It is an arithmetic number, because the mean of its divisors is an integer number (3352041).

Almost surely, 2^21343556 is an apocalyptic number.

21343556 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21343556 is a deficient number, since it is larger than the sum of its proper divisors (18880936).

21343556 is a wasteful number, since it uses less digits than its factorization.

21343556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410470 (or 410468 counting only the distinct ones).

The product of its digits is 10800, while the sum is 29.

The square root of 21343556 is about 4619.9086571057. The cubic root of 21343556 is about 277.3888026736.

Adding to 21343556 its reverse (65534312), we get a palindrome (86877868).

The spelling of 21343556 in words is "twenty-one million, three hundred forty-three thousand, five hundred fifty-six".