19806444 has 144 divisors (see below), whose sum is σ = 61641216. Its totient is φ = 5443200.

The previous prime is 19806443. The next prime is 19806461. The reversal of 19806444 is 44460891.

It is a happy number.

19806444 is a `hidden beast` number, since 1 + 9 + 8 + 0 + 644 + 4 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 19806399 and 19806408.

It is not an unprimeable number, because it can be changed into a prime (19806443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 278929 + ... + 278999.

It is an arithmetic number, because the mean of its divisors is an integer number (428064).

Almost surely, 2^19806444 is an apocalyptic number.

19806444 is a gapful number since it is divisible by the number (14) 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 19806444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30820608).

19806444 is an abundant number, since it is smaller than the sum of its proper divisors (41834772).

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

19806444 is a wasteful number, since it uses less digits than its factorization.

19806444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138 (or 124 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 19806444 is about 4450.4431240046. The cubic root of 19806444 is about 270.5632685478.

The spelling of 19806444 in words is "nineteen million, eight hundred six thousand, four hundred forty-four".