19840440 has 64 divisors (see below), whose sum is σ = 60147360. Its totient is φ = 5235200.

The previous prime is 19840417. The next prime is 19840441. The reversal of 19840440 is 4404891.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 19840398 and 19840407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19840441) 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, 11302 + ... + 12938.

Almost surely, 2^19840440 is an apocalyptic number.

19840440 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 19840440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30073680).

19840440 is an abundant number, since it is smaller than the sum of its proper divisors (40306920).

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

19840440 is a wasteful number, since it uses less digits than its factorization.

19840440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1752 (or 1748 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 19840440 is about 4454.2608814482. The cubic root of 19840440 is about 270.7179793301.

The spelling of 19840440 in words is "nineteen million, eight hundred forty thousand, four hundred forty".