665716061 has 2 divisors, whose sum is σ = 665716062. Its totient is φ = 665716060.

The previous prime is 665716049. The next prime is 665716063. The reversal of 665716061 is 160617566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 432390436 + 233325625 = 20794^2 + 15275^2 .

It is a cyclic number.

It is not a de Polignac number, because 665716061 - 2²⁶ = 598607197 is a prime.

Together with 665716063, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665716063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332858030 + 332858031.

It is an arithmetic number, because the mean of its divisors is an integer number (332858031).

Almost surely, 2^665716061 is an apocalyptic number.

It is an amenable number.

665716061 is a deficient number, since it is larger than the sum of its proper divisors (1).

665716061 is an equidigital number, since it uses as much as digits as its factorization.

665716061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 45360, while the sum is 38.

The square root of 665716061 is about 25801.4740082810. The cubic root of 665716061 is about 873.1650519568.

The spelling of 665716061 in words is "six hundred sixty-five million, seven hundred sixteen thousand, sixty-one".