19998481 has 2 divisors, whose sum is σ = 19998482. Its totient is φ = 19998480.

The previous prime is 19998479. The next prime is 19998491. The reversal of 19998481 is 18489991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17305600 + 2692881 = 4160^2 + 1641^2 .

It is a cyclic number.

It is not a de Polignac number, because 19998481 - 2¹ = 19998479 is a prime.

It is a super-2 number, since 2×19998481² = 799878484614722, which contains 22 as substring.

Together with 19998479, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (19998491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9999240 + 9999241.

It is an arithmetic number, because the mean of its divisors is an integer number (9999241).

Almost surely, 2^19998481 is an apocalyptic number.

It is an amenable number.

19998481 is a deficient number, since it is larger than the sum of its proper divisors (1).

19998481 is an equidigital number, since it uses as much as digits as its factorization.

19998481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 186624, while the sum is 49.

The square root of 19998481 is about 4471.9661224119. The cubic root of 19998481 is about 271.4348894849.

The spelling of 19998481 in words is "nineteen million, nine hundred ninety-eight thousand, four hundred eighty-one".