167716721 has 2 divisors, whose sum is σ = 167716722. Its totient is φ = 167716720.

The previous prime is 167716693. The next prime is 167716723. The reversal of 167716721 is 127617761.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 166926400 + 790321 = 12920^2 + 889^2 .

It is an emirp because it is prime and its reverse (127617761) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-167716721 is a prime.

Together with 167716723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (167716723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83858360 + 83858361.

It is an arithmetic number, because the mean of its divisors is an integer number (83858361).

Almost surely, 2^167716721 is an apocalyptic number.

It is an amenable number.

167716721 is a deficient number, since it is larger than the sum of its proper divisors (1).

167716721 is an equidigital number, since it uses as much as digits as its factorization.

167716721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24696, while the sum is 38.

The square root of 167716721 is about 12950.5490617194. The cubic root of 167716721 is about 551.4745237801.

The spelling of 167716721 in words is "one hundred sixty-seven million, seven hundred sixteen thousand, seven hundred twenty-one".