19998553 has 2 divisors, whose sum is σ = 19998554. Its totient is φ = 19998552.

The previous prime is 19998551. The next prime is 19998571. The reversal of 19998553 is 35589991.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15705369 + 4293184 = 3963^2 + 2072^2 .

It is a cyclic number.

It is not a de Polignac number, because 19998553 - 2¹ = 19998551 is a prime.

Together with 19998551, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 19998497 and 19998506.

It is not a weakly prime, because it can be changed into another prime (19998551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9999276 + 9999277.

It is an arithmetic number, because the mean of its divisors is an integer number (9999277).

Almost surely, 2^19998553 is an apocalyptic number.

It is an amenable number.

19998553 is a deficient number, since it is larger than the sum of its proper divisors (1).

19998553 is an equidigital number, since it uses as much as digits as its factorization.

19998553 is an evil number, because the sum of its binary digits is even.

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

The square root of 19998553 is about 4471.9741725551. The cubic root of 19998553 is about 271.4352152311.

The spelling of 19998553 in words is "nineteen million, nine hundred ninety-eight thousand, five hundred fifty-three".