556321621 has 4 divisors (see below), whose sum is σ = 556425100. Its totient is φ = 556218144.

The previous prime is 556321613. The next prime is 556321639. The reversal of 556321621 is 126123655.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 433222596 + 123099025 = 20814^2 + 11095^2 .

It is a cyclic number.

It is not a de Polignac number, because 556321621 - 2³ = 556321613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (556321681) 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 3 ways as a sum of consecutive naturals, for example, 43206 + ... + 54583.

It is an arithmetic number, because the mean of its divisors is an integer number (139106275).

Almost surely, 2^556321621 is an apocalyptic number.

It is an amenable number.

556321621 is a deficient number, since it is larger than the sum of its proper divisors (103479).

556321621 is an equidigital number, since it uses as much as digits as its factorization.

556321621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103478.

The product of its digits is 10800, while the sum is 31.

The square root of 556321621 is about 23586.4711434331. The cubic root of 556321621 is about 822.4483738687.

The spelling of 556321621 in words is "five hundred fifty-six million, three hundred twenty-one thousand, six hundred twenty-one".