20618856 has 48 divisors (see below), whose sum is σ = 58275360. Its totient is φ = 6573600.

The previous prime is 20618837. The next prime is 20618863. The reversal of 20618856 is 65881602.

It is a happy number.

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 20618856.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4570 + ... + 7881.

It is an arithmetic number, because the mean of its divisors is an integer number (1214070).

Almost surely, 2^20618856 is an apocalyptic number.

It is an amenable number.

20618856 is an abundant number, since it is smaller than the sum of its proper divisors (37656504).

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

20618856 is a wasteful number, since it uses less digits than its factorization.

20618856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12486 (or 12479 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 20618856 is about 4540.7990486257. The cubic root of 20618856 is about 274.2130936837.

The spelling of 20618856 in words is "twenty million, six hundred eighteen thousand, eight hundred fifty-six".