19806540 has 96 divisors (see below), whose sum is σ = 60775680. Its totient is φ = 4790016.

The previous prime is 19806503. The next prime is 19806557. The reversal of 19806540 is 4560891.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 52071 + ... + 52449.

It is an arithmetic number, because the mean of its divisors is an integer number (633080).

Almost surely, 2^19806540 is an apocalyptic number.

19806540 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 19806540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30387840).

19806540 is an abundant number, since it is smaller than the sum of its proper divisors (40969140).

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

19806540 is a wasteful number, since it uses less digits than its factorization.

19806540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 471 (or 469 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 19806540 is about 4450.4539094344. The cubic root of 19806540 is about 270.5637056788.

The spelling of 19806540 in words is "nineteen million, eight hundred six thousand, five hundred forty".