19500121 has 2 divisors, whose sum is σ = 19500122. Its totient is φ = 19500120.

The previous prime is 19500109. The next prime is 19500127. The reversal of 19500121 is 12100591.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19044496 + 455625 = 4364^2 + 675^2 .

It is a cyclic number.

It is not a de Polignac number, because 19500121 - 2¹⁹ = 18975833 is a prime.

It is not a weakly prime, because it can be changed into another prime (19500127) 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, 9750060 + 9750061.

It is an arithmetic number, because the mean of its divisors is an integer number (9750061).

Almost surely, 2^19500121 is an apocalyptic number.

It is an amenable number.

19500121 is a deficient number, since it is larger than the sum of its proper divisors (1).

19500121 is an equidigital number, since it uses as much as digits as its factorization.

19500121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 90, while the sum is 19.

The square root of 19500121 is about 4415.8941336948. The cubic root of 19500121 is about 269.1611873286.

The spelling of 19500121 in words is "nineteen million, five hundred thousand, one hundred twenty-one".