861995247681 has 16 divisors (see below), whose sum is σ = 1221926000256. Its totient is φ = 539306841216.

The previous prime is 861995247667. The next prime is 861995247683. The reversal of 861995247681 is 186742599168.

It is not a de Polignac number, because 861995247681 - 2²⁵ = 861961693249 is a prime.

It is a super-2 number, since 2×861995247681² (a number of 25 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (861995247683) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 117851860 + ... + 117859173.

It is an arithmetic number, because the mean of its divisors is an integer number (76370375016).

Almost surely, 2^861995247681 is an apocalyptic number.

It is an amenable number.

861995247681 is a deficient number, since it is larger than the sum of its proper divisors (359930752575).

861995247681 is a wasteful number, since it uses less digits than its factorization.

861995247681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235711112.

The product of its digits is 52254720, while the sum is 66.

The spelling of 861995247681 in words is "eight hundred sixty-one billion, nine hundred ninety-five million, two hundred forty-seven thousand, six hundred eighty-one".