19998656 has 28 divisors (see below), whose sum is σ = 40142160. Its totient is φ = 9884160.

The previous prime is 19998653. The next prime is 19998677. The reversal of 19998656 is 65689991.

It is a junction number, because it is equal to n+sod(n) for n = 19998598 and 19998607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19998653) 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, 3941 + ... + 7451.

Almost surely, 2^19998656 is an apocalyptic number.

19998656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19998656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20071080).

19998656 is an abundant number, since it is smaller than the sum of its proper divisors (20143504).

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

19998656 is an equidigital number, since it uses as much as digits as its factorization.

19998656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3612 (or 3602 counting only the distinct ones).

The product of its digits is 1049760, while the sum is 53.

The square root of 19998656 is about 4471.9856887070. The cubic root of 19998656 is about 271.4356812278.

The spelling of 19998656 in words is "nineteen million, nine hundred ninety-eight thousand, six hundred fifty-six".