19959109 has 2 divisors, whose sum is σ = 19959110. Its totient is φ = 19959108.

The previous prime is 19959097. The next prime is 19959127. The reversal of 19959109 is 90195991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18404100 + 1555009 = 4290^2 + 1247^2 .

It is a cyclic number.

It is not a de Polignac number, because 19959109 - 2¹¹ = 19957061 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19959409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9979554 + 9979555.

It is an arithmetic number, because the mean of its divisors is an integer number (9979555).

Almost surely, 2^19959109 is an apocalyptic number.

It is an amenable number.

19959109 is a deficient number, since it is larger than the sum of its proper divisors (1).

19959109 is an equidigital number, since it uses as much as digits as its factorization.

19959109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32805, while the sum is 43.

The square root of 19959109 is about 4467.5618630300. The cubic root of 19959109 is about 271.2566433563.

The spelling of 19959109 in words is "nineteen million, nine hundred fifty-nine thousand, one hundred nine".