19997678 has 8 divisors (see below), whose sum is σ = 31761072. Its totient is φ = 9410656.

The previous prime is 19997657. The next prime is 19997683. The reversal of 19997678 is 87679991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 294050 + ... + 294117.

It is an arithmetic number, because the mean of its divisors is an integer number (3970134).

Almost surely, 2^19997678 is an apocalyptic number.

19997678 is a deficient number, since it is larger than the sum of its proper divisors (11763394).

19997678 is a wasteful number, since it uses less digits than its factorization.

19997678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 588186.

The product of its digits is 1714608, while the sum is 56.

The square root of 19997678 is about 4471.8763399718. The cubic root of 19997678 is about 271.4312564568.

The spelling of 19997678 in words is "nineteen million, nine hundred ninety-seven thousand, six hundred seventy-eight".