168721517387 has 2 divisors, whose sum is σ = 168721517388. Its totient is φ = 168721517386.

The previous prime is 168721517309. The next prime is 168721517413. The reversal of 168721517387 is 783715127861.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 168721517387 - 2³⁶ = 100002040651 is a prime.

It is not a weakly prime, because it can be changed into another prime (168721517687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84360758693 + 84360758694.

It is an arithmetic number, because the mean of its divisors is an integer number (84360758694).

Almost surely, 2^168721517387 is an apocalyptic number.

168721517387 is a deficient number, since it is larger than the sum of its proper divisors (1).

168721517387 is an equidigital number, since it uses as much as digits as its factorization.

168721517387 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3951360, while the sum is 56.

The spelling of 168721517387 in words is "one hundred sixty-eight billion, seven hundred twenty-one million, five hundred seventeen thousand, three hundred eighty-seven".