19947664 has 80 divisors (see below), whose sum is σ = 45800640. Its totient is φ = 8314880.

The previous prime is 19947643. The next prime is 19947703. The reversal of 19947664 is 46674991.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 176472 + ... + 176584.

It is an arithmetic number, because the mean of its divisors is an integer number (572508).

Almost surely, 2^19947664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19947664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22900320).

19947664 is an abundant number, since it is smaller than the sum of its proper divisors (25852976).

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

19947664 is a wasteful number, since it uses less digits than its factorization.

19947664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208 (or 202 counting only the distinct ones).

The product of its digits is 326592, while the sum is 46.

The square root of 19947664 is about 4466.2807793510. The cubic root of 19947664 is about 271.2047852319.

The spelling of 19947664 in words is "nineteen million, nine hundred forty-seven thousand, six hundred sixty-four".