139240009 has 2 divisors, whose sum is σ = 139240010. Its totient is φ = 139240008.

The previous prime is 139240001. The next prime is 139240019. The reversal of 139240009 is 900042931.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 139240000 + 9 = 11800^2 + 3^2 .

It is a cyclic number.

It is not a de Polignac number, because 139240009 - 2³ = 139240001 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (139240001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69620004 + 69620005.

It is an arithmetic number, because the mean of its divisors is an integer number (69620005).

Almost surely, 2^139240009 is an apocalyptic number.

It is an amenable number.

139240009 is a deficient number, since it is larger than the sum of its proper divisors (1).

139240009 is an equidigital number, since it uses as much as digits as its factorization.

139240009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 139240009 is about 11800.0003813559. Note that the first 3 decimals coincide. The cubic root of 139240009 is about 518.3081218172.

The spelling of 139240009 in words is "one hundred thirty-nine million, two hundred forty thousand, nine".