19966986 has 80 divisors (see below), whose sum is σ = 50820000. Its totient is φ = 5808672.

The previous prime is 19966951. The next prime is 19967047. The reversal of 19966986 is 68966991.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 39765 + ... + 40263.

It is an arithmetic number, because the mean of its divisors is an integer number (635250).

Almost surely, 2^19966986 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19966986, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25410000).

19966986 is an abundant number, since it is smaller than the sum of its proper divisors (30853014).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19966986 is a wasteful number, since it uses less digits than its factorization.

19966986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 545 (or 536 counting only the distinct ones).

The product of its digits is 1259712, while the sum is 54.

The square root of 19966986 is about 4468.4433531153. The cubic root of 19966986 is about 271.2923230979.

The spelling of 19966986 in words is "nineteen million, nine hundred sixty-six thousand, nine hundred eighty-six".