19956564 has 48 divisors (see below), whose sum is σ = 52012800. Its totient is φ = 6617088.

The previous prime is 19956557. The next prime is 19956569. The reversal of 19956564 is 46565991.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19956569) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27397 + ... + 28115.

It is an arithmetic number, because the mean of its divisors is an integer number (1083600).

Almost surely, 2^19956564 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 19956564, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26006400).

19956564 is an abundant number, since it is smaller than the sum of its proper divisors (32056236).

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

19956564 is a wasteful number, since it uses less digits than its factorization.

19956564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 989 (or 981 counting only the distinct ones).

The product of its digits is 291600, while the sum is 45.

The square root of 19956564 is about 4467.2770229750. The cubic root of 19956564 is about 271.2451134912.

The spelling of 19956564 in words is "nineteen million, nine hundred fifty-six thousand, five hundred sixty-four".