19978845 has 8 divisors (see below), whose sum is σ = 31966176. Its totient is φ = 10655376.

The previous prime is 19978843. The next prime is 19978867. The reversal of 19978845 is 54887991.

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

It is not a de Polignac number, because 19978845 - 2¹ = 19978843 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19978841) 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, 665947 + ... + 665976.

It is an arithmetic number, because the mean of its divisors is an integer number (3995772).

Almost surely, 2^19978845 is an apocalyptic number.

19978845 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19978845 is a deficient number, since it is larger than the sum of its proper divisors (11987331).

19978845 is a wasteful number, since it uses less digits than its factorization.

19978845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1331931.

The product of its digits is 725760, while the sum is 51.

The square root of 19978845 is about 4469.7701283176. The cubic root of 19978845 is about 271.3460220542.

The spelling of 19978845 in words is "nineteen million, nine hundred seventy-eight thousand, eight hundred forty-five".