19995523 has 2 divisors, whose sum is σ = 19995524. Its totient is φ = 19995522.

The previous prime is 19995497. The next prime is 19995551. The reversal of 19995523 is 32559991.

It is a weak prime.

It is an emirp because it is prime and its reverse (32559991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19995523 - 2⁵ = 19995491 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19995523.

It is not a weakly prime, because it can be changed into another prime (19995583) 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, 9997761 + 9997762.

It is an arithmetic number, because the mean of its divisors is an integer number (9997762).

Almost surely, 2^19995523 is an apocalyptic number.

19995523 is a deficient number, since it is larger than the sum of its proper divisors (1).

19995523 is an equidigital number, since it uses as much as digits as its factorization.

19995523 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 109350, while the sum is 43.

The square root of 19995523 is about 4471.6353831680. The cubic root of 19995523 is about 271.4215060686.

The spelling of 19995523 in words is "nineteen million, nine hundred ninety-five thousand, five hundred twenty-three".