665001641 has 2 divisors, whose sum is σ = 665001642. Its totient is φ = 665001640.

The previous prime is 665001619. The next prime is 665001661. The reversal of 665001641 is 146100566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 445843225 + 219158416 = 21115^2 + 14804^2 .

It is a cyclic number.

It is not a de Polignac number, because 665001641 - 2¹⁰ = 665000617 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (665001611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332500820 + 332500821.

It is an arithmetic number, because the mean of its divisors is an integer number (332500821).

Almost surely, 2^665001641 is an apocalyptic number.

It is an amenable number.

665001641 is a deficient number, since it is larger than the sum of its proper divisors (1).

665001641 is an equidigital number, since it uses as much as digits as its factorization.

665001641 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 665001641 is about 25787.6257340609. The cubic root of 665001641 is about 872.8525914879.

The spelling of 665001641 in words is "six hundred sixty-five million, one thousand, six hundred forty-one".