19981447 has 4 divisors (see below), whose sum is σ = 20015296. Its totient is φ = 19947600.

The previous prime is 19981427. The next prime is 19981463. The reversal of 19981447 is 74418991.

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 19981447 - 2¹⁵ = 19948679 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19981417) 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 in 3 ways as a sum of consecutive naturals, for example, 16023 + ... + 17224.

It is an arithmetic number, because the mean of its divisors is an integer number (5003824).

Almost surely, 2^19981447 is an apocalyptic number.

19981447 is a deficient number, since it is larger than the sum of its proper divisors (33849).

19981447 is an equidigital number, since it uses as much as digits as its factorization.

19981447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33848.

The product of its digits is 72576, while the sum is 43.

The square root of 19981447 is about 4470.0611852636. The cubic root of 19981447 is about 271.3578013755.

The spelling of 19981447 in words is "nineteen million, nine hundred eighty-one thousand, four hundred forty-seven".