75645209 has 2 divisors, whose sum is σ = 75645210. Its totient is φ = 75645208.

The previous prime is 75645197. The next prime is 75645217. The reversal of 75645209 is 90254657.

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., 72505225 + 3139984 = 8515^2 + 1772^2 .

It is an emirp because it is prime and its reverse (90254657) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 75645209 - 2²⁴ = 58867993 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (75645259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37822604 + 37822605.

It is an arithmetic number, because the mean of its divisors is an integer number (37822605).

Almost surely, 2^75645209 is an apocalyptic number.

It is an amenable number.

75645209 is a deficient number, since it is larger than the sum of its proper divisors (1).

75645209 is an equidigital number, since it uses as much as digits as its factorization.

75645209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 75600, while the sum is 38.

The square root of 75645209 is about 8697.4254236527. The cubic root of 75645209 is about 422.9221931941.

The spelling of 75645209 in words is "seventy-five million, six hundred forty-five thousand, two hundred nine".