21320056 has 8 divisors (see below), whose sum is σ = 39975120. Its totient is φ = 10660024.

The previous prime is 21320053. The next prime is 21320059. The reversal of 21320056 is 65002312.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21320053) and next prime (21320059).

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 (21320051) 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 as a sum of consecutive naturals, namely, 1332496 + ... + 1332511.

It is an arithmetic number, because the mean of its divisors is an integer number (4996890).

Almost surely, 2^21320056 is an apocalyptic number.

It is an amenable number.

21320056 is a deficient number, since it is larger than the sum of its proper divisors (18655064).

21320056 is a wasteful number, since it uses less digits than its factorization.

21320056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2665013 (or 2665009 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21320056 is about 4617.3646163152. The cubic root of 21320056 is about 277.2869603698.

Adding to 21320056 its reverse (65002312), we get a palindrome (86322368).

The spelling of 21320056 in words is "twenty-one million, three hundred twenty thousand, fifty-six".