555120721 has 3 divisors (see below), whose sum is σ = 555144283. Its totient is φ = 555097160.

The previous prime is 555120667. The next prime is 555120773. The reversal of 555120721 is 127021555.

The square root of 555120721 is 23561.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 115799121 + 439321600 = 10761^2 + 20960^2 .

It is not a de Polignac number, because 555120721 - 2⁷ = 555120593 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 555120721.

It is not an unprimeable number, because it can be changed into a prime (555120791) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 11781 + ... + 35341.

Almost surely, 2^555120721 is an apocalyptic number.

555120721 is the 23561-st square number.

555120721 is the 11781-st centered octagonal number.

It is an amenable number.

555120721 is a deficient number, since it is larger than the sum of its proper divisors (23562).

555120721 is an frugal number, since it uses more digits than its factorization.

555120721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47122 (or 23561 counting only the distinct ones).

The product of its (nonzero) digits is 3500, while the sum is 28.

The cubic root of 555120721 is about 821.8561566152.

The spelling of 555120721 in words is "five hundred fifty-five million, one hundred twenty thousand, seven hundred twenty-one".