19820440 has 16 divisors (see below), whose sum is σ = 44596080. Its totient is φ = 7928160.

The previous prime is 19820429. The next prime is 19820441. The reversal of 19820440 is 4402891.

It is a junction number, because it is equal to n+sod(n) for n = 19820399 and 19820408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19820441) 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, 247716 + ... + 247795.

It is an arithmetic number, because the mean of its divisors is an integer number (2787255).

Almost surely, 2^19820440 is an apocalyptic number.

19820440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19820440 is an abundant number, since it is smaller than the sum of its proper divisors (24775640).

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

19820440 is a wasteful number, since it uses less digits than its factorization.

19820440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 495522 (or 495518 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 19820440 is about 4452.0152740079. The cubic root of 19820440 is about 270.6269837018.

The spelling of 19820440 in words is "nineteen million, eight hundred twenty thousand, four hundred forty".