861083778916 has 9 divisors (see below), whose sum is σ = 1506899860921. Its totient is φ = 430540961512.

The previous prime is 861083778901. The next prime is 861083778917. The reversal of 861083778916 is 619877380168.

The square root of 861083778916 is 927946.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 163030212900 + 698053566016 = 403770^2 + 835496^2 .

It is a super-2 number, since 2×861083778916² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (861083778917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 1623906 + ... + 2087878.

Almost surely, 2^861083778916 is an apocalyptic number.

861083778916 is the 927946-th square number.

It is an amenable number.

861083778916 is a deficient number, since it is larger than the sum of its proper divisors (645816082005).

861083778916 is an frugal number, since it uses more digits than its factorization.

861083778916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 927950 (or 463975 counting only the distinct ones).

The product of its (nonzero) digits is 24385536, while the sum is 64.

Multiplying 861083778916 by its sum of digits (64), we get a square (55109361850624 = 7423568²).

The spelling of 861083778916 in words is "eight hundred sixty-one billion, eighty-three million, seven hundred seventy-eight thousand, nine hundred sixteen".