20550816 has 144 divisors (see below), whose sum is σ = 68796000. Its totient is φ = 5736960.

The previous prime is 20550809. The next prime is 20550857. The reversal of 20550816 is 61805502.

It is a tau number, because it is divible by the number of its divisors (144).

It is a self number, because there is not a number n which added to its sum of digits gives 20550816.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 40935 + ... + 41433.

It is an arithmetic number, because the mean of its divisors is an integer number (477750).

Almost surely, 2^20550816 is an apocalyptic number.

20550816 is a gapful number since it is divisible by the number (26) 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 20550816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34398000).

20550816 is an abundant number, since it is smaller than the sum of its proper divisors (48245184).

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

20550816 is a wasteful number, since it uses less digits than its factorization.

20550816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 539 (or 528 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 20550816 is about 4533.3007841969. The cubic root of 20550816 is about 273.9111367576.

The spelling of 20550816 in words is "twenty million, five hundred fifty thousand, eight hundred sixteen".