1205640259 has 2 divisors, whose sum is σ = 1205640260. Its totient is φ = 1205640258.

The previous prime is 1205640239. The next prime is 1205640263. The reversal of 1205640259 is 9520465021.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (9520465021) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1205640259 is a prime.

It is not a weakly prime, because it can be changed into another prime (1205640239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 602820129 + 602820130.

It is an arithmetic number, because the mean of its divisors is an integer number (602820130).

Almost surely, 2^1205640259 is an apocalyptic number.

1205640259 is a deficient number, since it is larger than the sum of its proper divisors (1).

1205640259 is an equidigital number, since it uses as much as digits as its factorization.

1205640259 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21600, while the sum is 34.

The square root of 1205640259 is about 34722.3308405412. The cubic root of 1205640259 is about 1064.3208757075.

The spelling of 1205640259 in words is "one billion, two hundred five million, six hundred forty thousand, two hundred fifty-nine".