861803540989 has 2 divisors, whose sum is σ = 861803540990. Its totient is φ = 861803540988.

The previous prime is 861803540977. The next prime is 861803540999. The reversal of 861803540989 is 989045308168.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 536800932889 + 325002608100 = 732667^2 + 570090^2 .

It is a cyclic number.

It is not a de Polignac number, because 861803540989 - 2²¹ = 861801443837 is a prime.

It is a super-2 number, since 2×861803540989² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861803540999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430901770494 + 430901770495.

It is an arithmetic number, because the mean of its divisors is an integer number (430901770495).

Almost surely, 2^861803540989 is an apocalyptic number.

It is an amenable number.

861803540989 is a deficient number, since it is larger than the sum of its proper divisors (1).

861803540989 is an equidigital number, since it uses as much as digits as its factorization.

861803540989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14929920, while the sum is 61.

The spelling of 861803540989 in words is "eight hundred sixty-one billion, eight hundred three million, five hundred forty thousand, nine hundred eighty-nine".