19985564 has 12 divisors (see below), whose sum is σ = 35497224. Its totient is φ = 9843504.

The previous prime is 19985543. The next prime is 19985579. The reversal of 19985564 is 46558991.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37019 + ... + 37554.

It is an arithmetic number, because the mean of its divisors is an integer number (2958102).

Almost surely, 2^19985564 is an apocalyptic number.

It is an amenable number.

19985564 is a deficient number, since it is larger than the sum of its proper divisors (15511660).

19985564 is a wasteful number, since it uses less digits than its factorization.

19985564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74644 (or 74642 counting only the distinct ones).

The product of its digits is 388800, while the sum is 47.

The square root of 19985564 is about 4470.5216697831. The cubic root of 19985564 is about 271.3764370520.

The spelling of 19985564 in words is "nineteen million, nine hundred eighty-five thousand, five hundred sixty-four".