556198021 has 4 divisors (see below), whose sum is σ = 564499552. Its totient is φ = 547896492.

The previous prime is 556198007. The next prime is 556198031. The reversal of 556198021 is 120891655.

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: 120891655 = 5 ⋅24178331.

It is a cyclic number.

It is not a de Polignac number, because 556198021 - 2²⁹ = 19327109 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 (556198031) 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, 4150665 + ... + 4150798.

It is an arithmetic number, because the mean of its divisors is an integer number (141124888).

Almost surely, 2^556198021 is an apocalyptic number.

It is an amenable number.

556198021 is a deficient number, since it is larger than the sum of its proper divisors (8301531).

556198021 is an equidigital number, since it uses as much as digits as its factorization.

556198021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8301530.

The product of its (nonzero) digits is 21600, while the sum is 37.

The square root of 556198021 is about 23583.8508518011. The cubic root of 556198021 is about 822.3874605742.

The spelling of 556198021 in words is "five hundred fifty-six million, one hundred ninety-eight thousand, twenty-one".