551984021 has 2 divisors, whose sum is σ = 551984022. Its totient is φ = 551984020.

The previous prime is 551983921. The next prime is 551984023. The reversal of 551984021 is 120489155.

551984021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 541492900 + 10491121 = 23270^2 + 3239^2 .

It is a cyclic number.

It is not a de Polignac number, because 551984021 - 2¹⁰ = 551982997 is a prime.

Together with 551984023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (551984023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 275992010 + 275992011.

It is an arithmetic number, because the mean of its divisors is an integer number (275992011).

Almost surely, 2^551984021 is an apocalyptic number.

It is an amenable number.

551984021 is a deficient number, since it is larger than the sum of its proper divisors (1).

551984021 is an equidigital number, since it uses as much as digits as its factorization.

551984021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14400, while the sum is 35.

The square root of 551984021 is about 23494.3401907779. The cubic root of 551984021 is about 820.3052705353.

The spelling of 551984021 in words is "five hundred fifty-one million, nine hundred eighty-four thousand, twenty-one".