19998535 has 4 divisors (see below), whose sum is σ = 23998248. Its totient is φ = 15998824.

The previous prime is 19998533. The next prime is 19998541. The reversal of 19998535 is 53589991.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19998535 - 2¹ = 19998533 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19998533) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1999849 + ... + 1999858.

It is an arithmetic number, because the mean of its divisors is an integer number (5999562).

Almost surely, 2^19998535 is an apocalyptic number.

19998535 is a deficient number, since it is larger than the sum of its proper divisors (3999713).

19998535 is an equidigital number, since it uses as much as digits as its factorization.

19998535 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3999712.

The product of its digits is 437400, while the sum is 49.

The square root of 19998535 is about 4471.9721600207. The cubic root of 19998535 is about 271.4351337946.

The spelling of 19998535 in words is "nineteen million, nine hundred ninety-eight thousand, five hundred thirty-five".