861557755139 has 2 divisors, whose sum is σ = 861557755140. Its totient is φ = 861557755138.

The previous prime is 861557755129. The next prime is 861557755183. The reversal of 861557755139 is 931557755168.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-861557755139 is a prime.

It is not a weakly prime, because it can be changed into another prime (861557755129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430778877569 + 430778877570.

It is an arithmetic number, because the mean of its divisors is an integer number (430778877570).

Almost surely, 2^861557755139 is an apocalyptic number.

861557755139 is a deficient number, since it is larger than the sum of its proper divisors (1).

861557755139 is an equidigital number, since it uses as much as digits as its factorization.

861557755139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 39690000, while the sum is 62.

The spelling of 861557755139 in words is "eight hundred sixty-one billion, five hundred fifty-seven million, seven hundred fifty-five thousand, one hundred thirty-nine".