611686666816 has 63 divisors (see below), whose sum is σ = 1235483189049. Its totient is φ = 300478099968.

The previous prime is 611686666699. The next prime is 611686666841. The reversal of 611686666816 is 618666686116.

It is a happy number.

The square root of 611686666816 is 782104.

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., 194763342400 + 416923324416 = 441320^2 + 645696^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 369152260 + ... + 369153916.

Almost surely, 2^611686666816 is an apocalyptic number.

611686666816 is the 782104-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 611686666816

611686666816 is an abundant number, since it is smaller than the sum of its proper divisors (623796522233).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

611686666816 is an frugal number, since it uses more digits than its factorization.

611686666816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3444 (or 1718 counting only the distinct ones).

The product of its digits is 17915904, while the sum is 61.

The spelling of 611686666816 in words is "six hundred eleven billion, six hundred eighty-six million, six hundred sixty-six thousand, eight hundred sixteen".