66736609 has 2 divisors, whose sum is σ = 66736610. Its totient is φ = 66736608.

The previous prime is 66736603. The next prime is 66736619. The reversal of 66736609 is 90663766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 59830225 + 6906384 = 7735^2 + 2628^2 .

It is a cyclic number.

It is not a de Polignac number, because 66736609 - 2¹⁷ = 66605537 is a prime.

It is a super-4 number, since 4×66736609⁴ (a number of 32 digits) contains 4444 as substring.

It is not a weakly prime, because it can be changed into another prime (66736603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33368304 + 33368305.

It is an arithmetic number, because the mean of its divisors is an integer number (33368305).

Almost surely, 2^66736609 is an apocalyptic number.

It is an amenable number.

66736609 is a deficient number, since it is larger than the sum of its proper divisors (1).

66736609 is an equidigital number, since it uses as much as digits as its factorization.

66736609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 244944, while the sum is 43.

The square root of 66736609 is about 8169.2477621872. The cubic root of 66736609 is about 405.6218846107.

The spelling of 66736609 in words is "sixty-six million, seven hundred thirty-six thousand, six hundred nine".