66611537 has 2 divisors, whose sum is σ = 66611538. Its totient is φ = 66611536.

The previous prime is 66611533. The next prime is 66611539. The reversal of 66611537 is 73511666.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52765696 + 13845841 = 7264^2 + 3721^2 .

It is a cyclic number.

It is not a de Polignac number, because 66611537 - 2² = 66611533 is a prime.

Together with 66611539, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 66611497 and 66611506.

It is not a weakly prime, because it can be changed into another prime (66611533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33305768 + 33305769.

It is an arithmetic number, because the mean of its divisors is an integer number (33305769).

Almost surely, 2^66611537 is an apocalyptic number.

It is an amenable number.

66611537 is a deficient number, since it is larger than the sum of its proper divisors (1).

66611537 is an equidigital number, since it uses as much as digits as its factorization.

66611537 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22680, while the sum is 35.

The square root of 66611537 is about 8161.5891222237. The cubic root of 66611537 is about 405.3683322920.

The spelling of 66611537 in words is "sixty-six million, six hundred eleven thousand, five hundred thirty-seven".