19818540 has 192 divisors, whose sum is σ = 72576000. Its totient is φ = 4487616.

The previous prime is 19818529. The next prime is 19818587. The reversal of 19818540 is 4581891.

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 = 19818495 and 19818504.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 185167 + ... + 185273.

It is an arithmetic number, because the mean of its divisors is an integer number (378000).

Almost surely, 2^19818540 is an apocalyptic number.

19818540 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 19818540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36288000).

19818540 is an abundant number, since it is smaller than the sum of its proper divisors (52757460).

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

19818540 is a wasteful number, since it uses less digits than its factorization.

19818540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146 (or 124 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 19818540 is about 4451.8018823843. The cubic root of 19818540 is about 270.6183359338.

The spelling of 19818540 in words is "nineteen million, eight hundred eighteen thousand, five hundred forty".