45491209 has 2 divisors, whose sum is σ = 45491210. Its totient is φ = 45491208.

The previous prime is 45491207. The next prime is 45491219. The reversal of 45491209 is 90219454.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24285184 + 21206025 = 4928^2 + 4605^2 .

It is a cyclic number.

It is not a de Polignac number, because 45491209 - 2¹ = 45491207 is a prime.

Together with 45491207, it forms a pair of twin primes.

It is equal to p_2746177 and since 45491209 and 2746177 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (45491203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22745604 + 22745605.

It is an arithmetic number, because the mean of its divisors is an integer number (22745605).

Almost surely, 2^45491209 is an apocalyptic number.

It is an amenable number.

45491209 is a deficient number, since it is larger than the sum of its proper divisors (1).

45491209 is an equidigital number, since it uses as much as digits as its factorization.

45491209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 45491209 is about 6744.7171178634. The cubic root of 45491209 is about 356.9788556499.

The spelling of 45491209 in words is "forty-five million, four hundred ninety-one thousand, two hundred nine".