555721 has 4 divisors (see below), whose sum is σ = 565200. Its totient is φ = 546244.

The previous prime is 555707. The next prime is 555739. The reversal of 555721 is 127555.

It is a happy number.

555721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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.

It is a cyclic number.

It is not a de Polignac number, because 555721 - 2⁷ = 555593 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (555761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4651 + ... + 4768.

It is an arithmetic number, because the mean of its divisors is an integer number (141300).

2⁵⁵⁵⁷²¹ is an apocalyptic number.

It is an amenable number.

555721 is a deficient number, since it is larger than the sum of its proper divisors (9479).

555721 is an equidigital number, since it uses as much as digits as its factorization.

555721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9478.

The product of its digits is 1750, while the sum is 25.

The square root of 555721 is about 745.4669677457. The cubic root of 555721 is about 82.2152287562.

It can be divided in two parts, 55 and 5721, that added together give a square (5776 = 76²).

The spelling of 555721 in words is "five hundred fifty-five thousand, seven hundred twenty-one".