19668420 has 168 divisors, whose sum is σ = 66104640. Its totient is φ = 4898880.

The previous prime is 19668403. The next prime is 19668421. The reversal of 19668420 is 2486691.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19668421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 276985 + ... + 277055.

It is an arithmetic number, because the mean of its divisors is an integer number (393480).

Almost surely, 2^19668420 is an apocalyptic number.

19668420 is a gapful number since it is divisible by the number (10) 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 19668420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33052320).

19668420 is an abundant number, since it is smaller than the sum of its proper divisors (46436220).

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

19668420 is a wasteful number, since it uses less digits than its factorization.

19668420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 19668420 is about 4434.9092437163. The cubic root of 19668420 is about 269.9333168657.

The spelling of 19668420 in words is "nineteen million, six hundred sixty-eight thousand, four hundred twenty".