19681798 has 4 divisors (see below), whose sum is σ = 29522700. Its totient is φ = 9840898.

The previous prime is 19681789. The next prime is 19681841. The reversal of 19681798 is 89718691.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4920448 + ... + 4920451.

It is an arithmetic number, because the mean of its divisors is an integer number (7380675).

Almost surely, 2^19681798 is an apocalyptic number.

19681798 is a deficient number, since it is larger than the sum of its proper divisors (9840902).

19681798 is an equidigital number, since it uses as much as digits as its factorization.

19681798 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9840901.

The product of its digits is 217728, while the sum is 49.

The square root of 19681798 is about 4436.4172481857. The cubic root of 19681798 is about 269.9945037747.

The spelling of 19681798 in words is "nineteen million, six hundred eighty-one thousand, seven hundred ninety-eight".