661255206976 has 189 divisors, whose sum is σ = 1654340838759. Its totient is φ = 261361271808.

The previous prime is 661255206973. The next prime is 661255207049. The reversal of 661255206976 is 679602552166.

The square root of 661255206976 is 813176.

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

It can be written as a sum of positive squares in 4 ways, for example, as 446256064576 + 214999142400 = 668024^2 + 463680^2 .

It is not an unprimeable number, because it can be changed into a prime (661255206973) by changing a digit.

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 26 ways as a sum of consecutive naturals, for example, 591991570 + ... + 591992686.

It is an arithmetic number, because the mean of its divisors is an integer number (8753126131).

Almost surely, 2^661255206976 is an apocalyptic number.

661255206976 is the 813176-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661255206976

661255206976 is an abundant number, since it is smaller than the sum of its proper divisors (993085631783).

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

661255206976 is an equidigital number, since it uses as much as digits as its factorization.

661255206976 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2286 (or 1139 counting only the distinct ones).

The product of its (nonzero) digits is 8164800, while the sum is 55.

The spelling of 661255206976 in words is "six hundred sixty-one billion, two hundred fifty-five million, two hundred six thousand, nine hundred seventy-six".