19978444 has 12 divisors (see below), whose sum is σ = 36482544. Its totient is φ = 9554864.

The previous prime is 19978393. The next prime is 19978457. The reversal of 19978444 is 44487991.

It is a super-2 number, since 2×19978444² = 798276449322272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is a junction number, because it is equal to n+sod(n) for n = 19978394 and 19978403.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 108487 + ... + 108670.

It is an arithmetic number, because the mean of its divisors is an integer number (3040212).

Almost surely, 2^19978444 is an apocalyptic number.

It is an amenable number.

19978444 is a deficient number, since it is larger than the sum of its proper divisors (16504100).

19978444 is a wasteful number, since it uses less digits than its factorization.

19978444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 217184 (or 217182 counting only the distinct ones).

The product of its digits is 290304, while the sum is 46.

The square root of 19978444 is about 4469.7252711996. The cubic root of 19978444 is about 271.3442066259.

The spelling of 19978444 in words is "nineteen million, nine hundred seventy-eight thousand, four hundred forty-four".