56216721 has 24 divisors (see below), whose sum is σ = 82851552. Its totient is φ = 33880000.

The previous prime is 56216707. The next prime is 56216731. The reversal of 56216721 is 12761265.

56216721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 56216721 - 2¹⁰ = 56215697 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (56216731) 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 in 23 ways as a sum of consecutive naturals, for example, 90805 + ... + 91421.

It is an arithmetic number, because the mean of its divisors is an integer number (3452148).

Almost surely, 2^56216721 is an apocalyptic number.

It is an amenable number.

56216721 is a deficient number, since it is larger than the sum of its proper divisors (26634831).

56216721 is a wasteful number, since it uses less digits than its factorization.

56216721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 893 (or 882 counting only the distinct ones).

The product of its digits is 5040, while the sum is 30.

The square root of 56216721 is about 7497.7810717572. The cubic root of 56216721 is about 383.0791397746.

Adding to 56216721 its reverse (12761265), we get a palindrome (68977986).

The spelling of 56216721 in words is "fifty-six million, two hundred sixteen thousand, seven hundred twenty-one".