56553721 has 4 divisors (see below), whose sum is σ = 64632832. Its totient is φ = 48474612.

The previous prime is 56553691. The next prime is 56553733. The reversal of 56553721 is 12735565.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12735565 = 5 ⋅2547113.

It is a cyclic number.

It is not a de Polignac number, because 56553721 - 2⁵ = 56553689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (56553121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4039545 + ... + 4039558.

It is an arithmetic number, because the mean of its divisors is an integer number (16158208).

Almost surely, 2^56553721 is an apocalyptic number.

It is an amenable number.

56553721 is a deficient number, since it is larger than the sum of its proper divisors (8079111).

56553721 is an equidigital number, since it uses as much as digits as its factorization.

56553721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8079110.

The product of its digits is 31500, while the sum is 34.

The square root of 56553721 is about 7520.2208079284. The cubic root of 56553721 is about 383.8430913657.

The spelling of 56553721 in words is "fifty-six million, five hundred fifty-three thousand, seven hundred twenty-one".