19519561 has 2 divisors, whose sum is σ = 19519562. Its totient is φ = 19519560.

The previous prime is 19519541. The next prime is 19519589. The reversal of 19519561 is 16591591.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18966025 + 553536 = 4355^2 + 744^2 .

It is an emirp because it is prime and its reverse (16591591) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19519561 - 2¹⁵ = 19486793 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19519561.

It is not a weakly prime, because it can be changed into another prime (19519531) 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, 9759780 + 9759781.

It is an arithmetic number, because the mean of its divisors is an integer number (9759781).

Almost surely, 2^19519561 is an apocalyptic number.

It is an amenable number.

19519561 is a deficient number, since it is larger than the sum of its proper divisors (1).

19519561 is an equidigital number, since it uses as much as digits as its factorization.

19519561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12150, while the sum is 37.

The square root of 19519561 is about 4418.0947251049. The cubic root of 19519561 is about 269.2506014004.

The spelling of 19519561 in words is "nineteen million, five hundred nineteen thousand, five hundred sixty-one".