21200056 has 8 divisors (see below), whose sum is σ = 39750120. Its totient is φ = 10600024.

The previous prime is 21200051. The next prime is 21200077. The reversal of 21200056 is 65000212.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21200051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1324996 + ... + 1325011.

It is an arithmetic number, because the mean of its divisors is an integer number (4968765).

Almost surely, 2^21200056 is an apocalyptic number.

It is an amenable number.

21200056 is a deficient number, since it is larger than the sum of its proper divisors (18550064).

21200056 is a wasteful number, since it uses less digits than its factorization.

21200056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2650013 (or 2650009 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21200056 is about 4604.3518544959. The cubic root of 21200056 is about 276.7657444216.

Adding to 21200056 its reverse (65000212), we get a palindrome (86200268).

The spelling of 21200056 in words is "twenty-one million, two hundred thousand, fifty-six".