20104728817 has 4 divisors (see below), whose sum is σ = 20206783476. Its totient is φ = 20002674160.

The previous prime is 20104728803. The next prime is 20104728823. The reversal of 20104728817 is 71882740102.

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 16852193856 + 3252534961 = 129816^2 + 57031^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20104728817 is a prime.

It is a super-2 number, since 2×20104728817² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20104728817.

It is not an unprimeable number, because it can be changed into a prime (20104728827) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51027034 + ... + 51027427.

It is an arithmetic number, because the mean of its divisors is an integer number (5051695869).

Almost surely, 2^20104728817 is an apocalyptic number.

It is an amenable number.

20104728817 is a deficient number, since it is larger than the sum of its proper divisors (102054659).

20104728817 is a wasteful number, since it uses less digits than its factorization.

20104728817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102054658.

The product of its (nonzero) digits is 50176, while the sum is 40.

The spelling of 20104728817 in words is "twenty billion, one hundred four million, seven hundred twenty-eight thousand, eight hundred seventeen".