20537856 has 60 divisors (see below), whose sum is σ = 59286942. Its totient is φ = 6844416.

The previous prime is 20537851. The next prime is 20537861. The reversal of 20537856 is 65873502.

It is an interprime number because it is at equal distance from previous prime (20537851) and next prime (20537861).

It can be written as a sum of positive squares in only one way, i.e., 15872256 + 4665600 = 3984^2 + 2160^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 20537856.

It is not an unprimeable number, because it can be changed into a prime (20537851) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2380 + ... + 6836.

Almost surely, 2^20537856 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 20537856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29643471).

20537856 is an abundant number, since it is smaller than the sum of its proper divisors (38749086).

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

20537856 is an equidigital number, since it uses as much as digits as its factorization.

20537856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4481 (or 4462 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The square root of 20537856 is about 4531.8711367381. The cubic root of 20537856 is about 273.8535456167.

The spelling of 20537856 in words is "twenty million, five hundred thirty-seven thousand, eight hundred fifty-six".