66531917 has 2 divisors, whose sum is σ = 66531918. Its totient is φ = 66531916.

The previous prime is 66531911. The next prime is 66531929. The reversal of 66531917 is 71913566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66275881 + 256036 = 8141^2 + 506^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66531917 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66531911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33265958 + 33265959.

It is an arithmetic number, because the mean of its divisors is an integer number (33265959).

Almost surely, 2^66531917 is an apocalyptic number.

It is an amenable number.

66531917 is a deficient number, since it is larger than the sum of its proper divisors (1).

66531917 is an equidigital number, since it uses as much as digits as its factorization.

66531917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34020, while the sum is 38.

The square root of 66531917 is about 8156.7099372235. The cubic root of 66531917 is about 405.2067572051.

The spelling of 66531917 in words is "sixty-six million, five hundred thirty-one thousand, nine hundred seventeen".