66212761 has 2 divisors, whose sum is σ = 66212762. Its totient is φ = 66212760.

The previous prime is 66212759. The next prime is 66212779. The reversal of 66212761 is 16721266.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66015625 + 197136 = 8125^2 + 444^2 .

It is a cyclic number.

It is not a de Polignac number, because 66212761 - 2¹ = 66212759 is a prime.

Together with 66212759, 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 (66212711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33106380 + 33106381.

It is an arithmetic number, because the mean of its divisors is an integer number (33106381).

Almost surely, 2^66212761 is an apocalyptic number.

It is an amenable number.

66212761 is a deficient number, since it is larger than the sum of its proper divisors (1).

66212761 is an equidigital number, since it uses as much as digits as its factorization.

66212761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6048, while the sum is 31.

The square root of 66212761 is about 8137.1224029137. The cubic root of 66212761 is about 404.5577879213.

The spelling of 66212761 in words is "sixty-six million, two hundred twelve thousand, seven hundred sixty-one".