19981499 has 4 divisors (see below), whose sum is σ = 20009136. Its totient is φ = 19953864.

The previous prime is 19981463. The next prime is 19981523. The reversal of 19981499 is 99418991.

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 19981499 - 2⁸ = 19981243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19981399) 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 in 3 ways as a sum of consecutive naturals, for example, 12704 + ... + 14189.

It is an arithmetic number, because the mean of its divisors is an integer number (5002284).

Almost surely, 2^19981499 is an apocalyptic number.

19981499 is a deficient number, since it is larger than the sum of its proper divisors (27637).

19981499 is an equidigital number, since it uses as much as digits as its factorization.

19981499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27636.

The product of its digits is 209952, while the sum is 50.

The square root of 19981499 is about 4470.0670017350. The cubic root of 19981499 is about 271.3580367704.

The spelling of 19981499 in words is "nineteen million, nine hundred eighty-one thousand, four hundred ninety-nine".