55421909 has 2 divisors, whose sum is σ = 55421910. Its totient is φ = 55421908.

The previous prime is 55421903. The next prime is 55421923. The reversal of 55421909 is 90912455.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 34692100 + 20729809 = 5890^2 + 4553^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55421909 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55421903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27710954 + 27710955.

It is an arithmetic number, because the mean of its divisors is an integer number (27710955).

Almost surely, 2^55421909 is an apocalyptic number.

It is an amenable number.

55421909 is a deficient number, since it is larger than the sum of its proper divisors (1).

55421909 is an equidigital number, since it uses as much as digits as its factorization.

55421909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16200, while the sum is 35.

The square root of 55421909 is about 7444.5892432021. The cubic root of 55421909 is about 381.2651942704.

The spelling of 55421909 in words is "fifty-five million, four hundred twenty-one thousand, nine hundred nine".