861611291 has 2 divisors, whose sum is σ = 861611292. Its totient is φ = 861611290.

The previous prime is 861611273. The next prime is 861611347. The reversal of 861611291 is 192116168.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-861611291 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (861511291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430805645 + 430805646.

It is an arithmetic number, because the mean of its divisors is an integer number (430805646).

Almost surely, 2^861611291 is an apocalyptic number.

861611291 is a deficient number, since it is larger than the sum of its proper divisors (1).

861611291 is an equidigital number, since it uses as much as digits as its factorization.

861611291 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 35.

The square root of 861611291 is about 29353.2160248243. The cubic root of 861611291 is about 951.5620804862.

The spelling of 861611291 in words is "eight hundred sixty-one million, six hundred eleven thousand, two hundred ninety-one".