64545209 has 4 divisors (see below), whose sum is σ = 68342004. Its totient is φ = 60748416.

The previous prime is 64545191. The next prime is 64545211. The reversal of 64545209 is 90254546.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 34810000 + 29735209 = 5900^2 + 5453^2 .

It is a cyclic number.

It is not a de Polignac number, because 64545209 - 2²⁰ = 63496633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64545409) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1898372 + ... + 1898405.

It is an arithmetic number, because the mean of its divisors is an integer number (17085501).

Almost surely, 2^64545209 is an apocalyptic number.

It is an amenable number.

64545209 is a deficient number, since it is larger than the sum of its proper divisors (3796795).

64545209 is a wasteful number, since it uses less digits than its factorization.

64545209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3796794.

The product of its (nonzero) digits is 43200, while the sum is 35.

The square root of 64545209 is about 8034.0032984808. The cubic root of 64545209 is about 401.1326418622.

It can be divided in two parts, 645 and 45209, that added together give a palindrome (45854).

The spelling of 64545209 in words is "sixty-four million, five hundred forty-five thousand, two hundred nine".