19639121 has 2 divisors, whose sum is σ = 19639122. Its totient is φ = 19639120.

The previous prime is 19639073. The next prime is 19639157. The reversal of 19639121 is 12193691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17977600 + 1661521 = 4240^2 + 1289^2 .

It is an emirp because it is prime and its reverse (12193691) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19639121 - 2⁶ = 19639057 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (19639181) 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, 9819560 + 9819561.

It is an arithmetic number, because the mean of its divisors is an integer number (9819561).

Almost surely, 2^19639121 is an apocalyptic number.

It is an amenable number.

19639121 is a deficient number, since it is larger than the sum of its proper divisors (1).

19639121 is an equidigital number, since it uses as much as digits as its factorization.

19639121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2916, while the sum is 32.

The square root of 19639121 is about 4431.6047883357. The cubic root of 19639121 is about 269.7992151500.

The spelling of 19639121 in words is "nineteen million, six hundred thirty-nine thousand, one hundred twenty-one".