550000021 has 2 divisors, whose sum is σ = 550000022. Its totient is φ = 550000020.

The previous prime is 550000007. The next prime is 550000091. The reversal of 550000021 is 120000055.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 447787921 + 102212100 = 21161^2 + 10110^2 .

It is a cyclic number.

It is not a de Polignac number, because 550000021 - 2⁷ = 549999893 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 549999956 and 550000010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (550000001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 275000010 + 275000011.

It is an arithmetic number, because the mean of its divisors is an integer number (275000011).

Almost surely, 2^550000021 is an apocalyptic number.

It is an amenable number.

550000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

550000021 is an equidigital number, since it uses as much as digits as its factorization.

550000021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 50, while the sum is 13.

The square root of 550000021 is about 23452.0792468386. The cubic root of 550000021 is about 819.3212810284.

Adding to 550000021 its reverse (120000055), we get a palindrome (670000076).

The spelling of 550000021 in words is "five hundred fifty million, twenty-one", and thus it is an aban number.