19540820 has 48 divisors (see below), whose sum is σ = 46802448. Its totient is φ = 6789120.

The previous prime is 19540817. The next prime is 19540853. The reversal of 19540820 is 2804591.

It can be written as a sum of positive squares in 8 ways, for example, as 75076 + 19465744 = 274^2 + 4412^2 .

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 2210 + ... + 6630.

It is an arithmetic number, because the mean of its divisors is an integer number (975051).

Almost surely, 2^19540820 is an apocalyptic number.

19540820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a pronic number, being equal to 4420×4421.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19540820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23401224).

19540820 is an abundant number, since it is smaller than the sum of its proper divisors (27261628).

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

19540820 is a wasteful number, since it uses less digits than its factorization.

19540820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4460 (or 4458 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 19540820 is about 4420.4999717227. The cubic root of 19540820 is about 269.3483140106.

The spelling of 19540820 in words is "nineteen million, five hundred forty thousand, eight hundred twenty".