20010816 has 126 divisors (see below), whose sum is σ = 66815970. Its totient is φ = 5709312.

The previous prime is 20010811. The next prime is 20010847. The reversal of 20010816 is 61801002.

It can be written as a sum of positive squares in only one way, i.e., 13660416 + 6350400 = 3696^2 + 2520^2 .

It is a tau number, because it is divible by the number of its divisors (126).

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 (20010811) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 27870 + ... + 28578.

Almost surely, 2^20010816 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 20010816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33407985).

20010816 is an abundant number, since it is smaller than the sum of its proper divisors (46805154).

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

20010816 is a wasteful number, since it uses less digits than its factorization.

20010816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 741 (or 721 counting only the distinct ones).

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

The square root of 20010816 is about 4473.3450571133. The cubic root of 20010816 is about 271.4906847429.

Adding to 20010816 its reverse (61801002), we get a palindrome (81811818).

The spelling of 20010816 in words is "twenty million, ten thousand, eight hundred sixteen".