167991503899561 has 2 divisors, whose sum is σ = 167991503899562. Its totient is φ = 167991503899560.

The previous prime is 167991503899507. The next prime is 167991503899649. The reversal of 167991503899561 is 165998305199761.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 127919628744336 + 40071875155225 = 11310156^2 + 6330235^2 .

It is an emirp because it is prime and its reverse (165998305199761) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 167991503899561 - 2¹⁷ = 167991503768489 is a prime.

It is a super-2 number, since 2×167991503899561² (a number of 29 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (167991503899501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83995751949780 + 83995751949781.

It is an arithmetic number, because the mean of its divisors is an integer number (83995751949781).

Almost surely, 2^{167991503899561} is an apocalyptic number.

It is an amenable number.

167991503899561 is a deficient number, since it is larger than the sum of its proper divisors (1).

167991503899561 is an equidigital number, since it uses as much as digits as its factorization.

167991503899561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 992023200, while the sum is 79.

The spelling of 167991503899561 in words is "one hundred sixty-seven trillion, nine hundred ninety-one billion, five hundred three million, eight hundred ninety-nine thousand, five hundred sixty-one".