164701721 has 2 divisors, whose sum is σ = 164701722. Its totient is φ = 164701720.

The previous prime is 164701717. The next prime is 164701741. The reversal of 164701721 is 127107461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 159037321 + 5664400 = 12611^2 + 2380^2 .

It is a cyclic number.

It is not a de Polignac number, because 164701721 - 2² = 164701717 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (164701741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82350860 + 82350861.

It is an arithmetic number, because the mean of its divisors is an integer number (82350861).

Almost surely, 2^164701721 is an apocalyptic number.

It is an amenable number.

164701721 is a deficient number, since it is larger than the sum of its proper divisors (1).

164701721 is an equidigital number, since it uses as much as digits as its factorization.

164701721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2352, while the sum is 29.

The square root of 164701721 is about 12833.6168323665. The cubic root of 164701721 is about 548.1499503072.

The spelling of 164701721 in words is "one hundred sixty-four million, seven hundred one thousand, seven hundred twenty-one".