20010817 has 4 divisors (see below), whose sum is σ = 20121556. Its totient is φ = 19900080.

The previous prime is 20010811. The next prime is 20010847. The reversal of 20010817 is 71801002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 571536 + 19439281 = 756^2 + 4409^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20010817 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20010794 and 20010803.

It is not an unprimeable number, because it can be changed into a prime (20010811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55098 + ... + 55459.

It is an arithmetic number, because the mean of its divisors is an integer number (5030389).

Almost surely, 2^20010817 is an apocalyptic number.

It is an amenable number.

20010817 is a deficient number, since it is larger than the sum of its proper divisors (110739).

20010817 is a wasteful number, since it uses less digits than its factorization.

20010817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110738.

The product of its (nonzero) digits is 112, while the sum is 19.

The square root of 20010817 is about 4473.3451688865. The cubic root of 20010817 is about 271.4906892653.

Adding to 20010817 its reverse (71801002), we get a palindrome (91811819).

The spelling of 20010817 in words is "twenty million, ten thousand, eight hundred seventeen".