19809998 has 16 divisors (see below), whose sum is σ = 33883920. Its totient is φ = 8605056.

The previous prime is 19809991. The next prime is 19810001. The reversal of 19809998 is 89990891.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19809991) 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 7 ways as a sum of consecutive naturals, for example, 21968 + ... + 22851.

It is an arithmetic number, because the mean of its divisors is an integer number (2117745).

Almost surely, 2^19809998 is an apocalyptic number.

19809998 is a deficient number, since it is larger than the sum of its proper divisors (14073922).

19809998 is a wasteful number, since it uses less digits than its factorization.

19809998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44851.

The product of its (nonzero) digits is 419904, while the sum is 53.

The square root of 19809998 is about 4450.8423921770. The cubic root of 19809998 is about 270.5794505599.

The spelling of 19809998 in words is "nineteen million, eight hundred nine thousand, nine hundred ninety-eight".