66868537 has 2 divisors, whose sum is σ = 66868538. Its totient is φ = 66868536.

The previous prime is 66868507. The next prime is 66868553. The reversal of 66868537 is 73586866.

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., 66194496 + 674041 = 8136^2 + 821^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66868537 is a prime.

It is not a weakly prime, because it can be changed into another prime (66868507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33434268 + 33434269.

It is an arithmetic number, because the mean of its divisors is an integer number (33434269).

Almost surely, 2^66868537 is an apocalyptic number.

It is an amenable number.

66868537 is a deficient number, since it is larger than the sum of its proper divisors (1).

66868537 is an equidigital number, since it uses as much as digits as its factorization.

66868537 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1451520, while the sum is 49.

The square root of 66868537 is about 8177.3184479999. The cubic root of 66868537 is about 405.8889926804. Note that the first 3 decimals are identical.

The spelling of 66868537 in words is "sixty-six million, eight hundred sixty-eight thousand, five hundred thirty-seven".