19998478 has 16 divisors (see below), whose sum is σ = 30518640. Its totient is φ = 9827136.

The previous prime is 19998427. The next prime is 19998479. The reversal of 19998478 is 87489991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19998479) 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 7 ways as a sum of consecutive naturals, for example, 50176 + ... + 50572.

It is an arithmetic number, because the mean of its divisors is an integer number (1907415).

Almost surely, 2^19998478 is an apocalyptic number.

19998478 is a deficient number, since it is larger than the sum of its proper divisors (10520162).

19998478 is a wasteful number, since it uses less digits than its factorization.

19998478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 771.

The product of its digits is 1306368, while the sum is 55.

The square root of 19998478 is about 4471.9657869890. The cubic root of 19998478 is about 271.4348759121.

The spelling of 19998478 in words is "nineteen million, nine hundred ninety-eight thousand, four hundred seventy-eight".