66615137 has 2 divisors, whose sum is σ = 66615138. Its totient is φ = 66615136.

The previous prime is 66615079. The next prime is 66615139. The reversal of 66615137 is 73151666.

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., 62710561 + 3904576 = 7919^2 + 1976^2 .

It is a cyclic number.

It is not a de Polignac number, because 66615137 - 2⁸ = 66614881 is a prime.

Together with 66615139, 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 = 66615097 and 66615106.

It is not a weakly prime, because it can be changed into another prime (66615139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33307568 + 33307569.

It is an arithmetic number, because the mean of its divisors is an integer number (33307569).

Almost surely, 2^66615137 is an apocalyptic number.

It is an amenable number.

66615137 is a deficient number, since it is larger than the sum of its proper divisors (1).

66615137 is an equidigital number, since it uses as much as digits as its factorization.

66615137 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 66615137 is about 8161.8096645291. The cubic root of 66615137 is about 405.3756348293.

The spelling of 66615137 in words is "sixty-six million, six hundred fifteen thousand, one hundred thirty-seven".