16520974717 has 4 divisors (see below), whose sum is σ = 17791818940. Its totient is φ = 15250130496.

The previous prime is 16520974709. The next prime is 16520974721. The reversal of 16520974717 is 71747902561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71747902561 = 307 ⋅233706523.

It can be written as a sum of positive squares in 2 ways, for example, as 2314956996 + 14206017721 = 48114^2 + 119189^2 .

It is a cyclic number.

It is not a de Polignac number, because 16520974717 - 2³ = 16520974709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16520974817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 635422092 + ... + 635422117.

It is an arithmetic number, because the mean of its divisors is an integer number (4447954735).

Almost surely, 2^16520974717 is an apocalyptic number.

It is an amenable number.

16520974717 is a deficient number, since it is larger than the sum of its proper divisors (1270844223).

16520974717 is a wasteful number, since it uses less digits than its factorization.

16520974717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1270844222.

The product of its (nonzero) digits is 740880, while the sum is 49.

The spelling of 16520974717 in words is "sixteen billion, five hundred twenty million, nine hundred seventy-four thousand, seven hundred seventeen".