19986644 has 12 divisors (see below), whose sum is σ = 35012544. Its totient is φ = 9983064.

The previous prime is 19986619. The next prime is 19986647. The reversal of 19986644 is 44668991.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19986647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3317 + ... + 7139.

It is an arithmetic number, because the mean of its divisors is an integer number (2917712).

Almost surely, 2^19986644 is an apocalyptic number.

It is an amenable number.

19986644 is a deficient number, since it is larger than the sum of its proper divisors (15025900).

19986644 is a wasteful number, since it uses less digits than its factorization.

19986644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5134 (or 5132 counting only the distinct ones).

The product of its digits is 373248, while the sum is 47.

The square root of 19986644 is about 4470.6424594235. The cubic root of 19986644 is about 271.3813252682.

The spelling of 19986644 in words is "nineteen million, nine hundred eighty-six thousand, six hundred forty-four".