861611539 has 2 divisors, whose sum is σ = 861611540. Its totient is φ = 861611538.

The previous prime is 861611477. The next prime is 861611593. The reversal of 861611539 is 935116168.

861611539 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

Together with next prime (861611593) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-861611539 is a prime.

It is not a weakly prime, because it can be changed into another prime (861611599) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430805769 + 430805770.

It is an arithmetic number, because the mean of its divisors is an integer number (430805770).

Almost surely, 2^861611539 is an apocalyptic number.

861611539 is a deficient number, since it is larger than the sum of its proper divisors (1).

861611539 is an equidigital number, since it uses as much as digits as its factorization.

861611539 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38880, while the sum is 40.

The square root of 861611539 is about 29353.2202492333. The cubic root of 861611539 is about 951.5621717831.

The spelling of 861611539 in words is "eight hundred sixty-one million, six hundred eleven thousand, five hundred thirty-nine".