149781209 has 2 divisors, whose sum is σ = 149781210. Its totient is φ = 149781208.

The previous prime is 149781197. The next prime is 149781223. The reversal of 149781209 is 902187941.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 131905225 + 17875984 = 11485^2 + 4228^2 .

It is a cyclic number.

It is not a de Polignac number, because 149781209 - 2¹² = 149777113 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (149781239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 74890604 + 74890605.

It is an arithmetic number, because the mean of its divisors is an integer number (74890605).

Almost surely, 2^149781209 is an apocalyptic number.

It is an amenable number.

149781209 is a deficient number, since it is larger than the sum of its proper divisors (1).

149781209 is an equidigital number, since it uses as much as digits as its factorization.

149781209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 41.

The square root of 149781209 is about 12238.5133492594. The cubic root of 149781209 is about 531.0708254082.

The spelling of 149781209 in words is "one hundred forty-nine million, seven hundred eighty-one thousand, two hundred nine".