19555121 has 2 divisors, whose sum is σ = 19555122. Its totient is φ = 19555120.

The previous prime is 19555111. The next prime is 19555139. The reversal of 19555121 is 12155591.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11826721 + 7728400 = 3439^2 + 2780^2 .

It is a cyclic number.

It is not a de Polignac number, because 19555121 - 2¹⁴ = 19538737 is a prime.

It is not a weakly prime, because it can be changed into another prime (19555111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9777560 + 9777561.

It is an arithmetic number, because the mean of its divisors is an integer number (9777561).

Almost surely, 2^19555121 is an apocalyptic number.

It is an amenable number.

19555121 is a deficient number, since it is larger than the sum of its proper divisors (1).

19555121 is an equidigital number, since it uses as much as digits as its factorization.

19555121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2250, while the sum is 29.

The square root of 19555121 is about 4422.1172530814. The cubic root of 19555121 is about 269.4140057426.

The spelling of 19555121 in words is "nineteen million, five hundred fifty-five thousand, one hundred twenty-one".