188720208517 has 2 divisors, whose sum is σ = 188720208518. Its totient is φ = 188720208516.

The previous prime is 188720208499. The next prime is 188720208541. The reversal of 188720208517 is 715802027881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 144277665921 + 44442542596 = 379839^2 + 210814^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-188720208517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (188720208917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94360104258 + 94360104259.

It is an arithmetic number, because the mean of its divisors is an integer number (94360104259).

Almost surely, 2^188720208517 is an apocalyptic number.

It is an amenable number.

188720208517 is a deficient number, since it is larger than the sum of its proper divisors (1).

188720208517 is an equidigital number, since it uses as much as digits as its factorization.

188720208517 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 501760, while the sum is 49.

The spelling of 188720208517 in words is "one hundred eighty-eight billion, seven hundred twenty million, two hundred eight thousand, five hundred seventeen".