20518416 has 60 divisors (see below), whose sum is σ = 58104540. Its totient is φ = 6758400.

The previous prime is 20518411. The next prime is 20518417. The reversal of 20518416 is 61481502.

It can be written as a sum of positive squares in 2 ways, for example, as 14288400 + 6230016 = 3780^2 + 2496^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20518416.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20518411) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12016 + ... + 13616.

It is an arithmetic number, because the mean of its divisors is an integer number (968409).

Almost surely, 2^20518416 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20518416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29052270).

20518416 is an abundant number, since it is smaller than the sum of its proper divisors (37586124).

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

20518416 is a wasteful number, since it uses less digits than its factorization.

20518416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1704 (or 1695 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 20518416 is about 4529.7258195171. The cubic root of 20518416 is about 273.7671134607.

Adding to 20518416 its reverse (61481502), we get a palindrome (81999918).

The spelling of 20518416 in words is "twenty million, five hundred eighteen thousand, four hundred sixteen".