20100816 has 30 divisors (see below), whose sum is σ = 56254770. Its totient is φ = 6700224.

The previous prime is 20100811. The next prime is 20100853. The reversal of 20100816 is 61800102.

It can be written as a sum of positive squares in only one way, i.e., 19395216 + 705600 = 4404^2 + 840^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20100811) 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, 69651 + ... + 69938.

It is an arithmetic number, because the mean of its divisors is an integer number (1875159).

Almost surely, 2^20100816 is an apocalyptic number.

It is an amenable number.

20100816 is an abundant number, since it is smaller than the sum of its proper divisors (36153954).

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

20100816 is a wasteful number, since it uses less digits than its factorization.

20100816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139603 (or 139594 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 20100816 is about 4483.3933577147. The cubic root of 20100816 is about 271.8970919821.

Adding to 20100816 its reverse (61800102), we get a palindrome (81900918).

The spelling of 20100816 in words is "twenty million, one hundred thousand, eight hundred sixteen".