66039997 has 2 divisors, whose sum is σ = 66039998. Its totient is φ = 66039996.

The previous prime is 66039979. The next prime is 66040033. The reversal of 66039997 is 79993066.

Together with previous prime (66039979) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64738116 + 1301881 = 8046^2 + 1141^2 .

It is a cyclic number.

It is not a de Polignac number, because 66039997 - 2²³ = 57651389 is a prime.

It is a super-2 number, since 2×66039997² = 8722562407520018, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 66039997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66039907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33019998 + 33019999.

It is an arithmetic number, because the mean of its divisors is an integer number (33019999).

Almost surely, 2^66039997 is an apocalyptic number.

It is an amenable number.

66039997 is a deficient number, since it is larger than the sum of its proper divisors (1).

66039997 is an equidigital number, since it uses as much as digits as its factorization.

66039997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 551124, while the sum is 49.

The square root of 66039997 is about 8126.4996769827. The cubic root of 66039997 is about 404.2056206665.

The spelling of 66039997 in words is "sixty-six million, thirty-nine thousand, nine hundred ninety-seven".