661266271 has 2 divisors, whose sum is σ = 661266272. Its totient is φ = 661266270.

The previous prime is 661266251. The next prime is 661266299. The reversal of 661266271 is 172662166.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661266271 - 2⁷ = 661266143 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661266271.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661266241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330633135 + 330633136.

It is an arithmetic number, because the mean of its divisors is an integer number (330633136).

Almost surely, 2^661266271 is an apocalyptic number.

661266271 is a deficient number, since it is larger than the sum of its proper divisors (1).

661266271 is an equidigital number, since it uses as much as digits as its factorization.

661266271 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 37.

The square root of 661266271 is about 25715.0981137541. The cubic root of 661266271 is about 871.2152265035.

The spelling of 661266271 in words is "six hundred sixty-one million, two hundred sixty-six thousand, two hundred seventy-one".