55021909 has 2 divisors, whose sum is σ = 55021910. Its totient is φ = 55021908.

The previous prime is 55021907. The next prime is 55021919. The reversal of 55021909 is 90912055.

55021909 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47748100 + 7273809 = 6910^2 + 2697^2 .

It is a cyclic number.

It is not a de Polignac number, because 55021909 - 2¹ = 55021907 is a prime.

Together with 55021907, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55021907) 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 as a sum of consecutive naturals, namely, 27510954 + 27510955.

It is an arithmetic number, because the mean of its divisors is an integer number (27510955).

Almost surely, 2^55021909 is an apocalyptic number.

It is an amenable number.

55021909 is a deficient number, since it is larger than the sum of its proper divisors (1).

55021909 is an equidigital number, since it uses as much as digits as its factorization.

55021909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4050, while the sum is 31.

The square root of 55021909 is about 7417.6754445042. The cubic root of 55021909 is about 380.3457356669.

The spelling of 55021909 in words is "fifty-five million, twenty-one thousand, nine hundred nine".