681517066 has 4 divisors (see below), whose sum is σ = 1022275602. Its totient is φ = 340758532.

The previous prime is 681517037. The next prime is 681517093. The reversal of 681517066 is 660715186.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 660715186 = 2 ⋅330357593.

It can be written as a sum of positive squares in only one way, i.e., 613800625 + 67716441 = 24775^2 + 8229^2 .

It is a super-3 number, since 3×681517066³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 170379265 + ... + 170379268.

Almost surely, 2^681517066 is an apocalyptic number.

681517066 is a deficient number, since it is larger than the sum of its proper divisors (340758536).

681517066 is a wasteful number, since it uses less digits than its factorization.

681517066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 340758535.

The product of its (nonzero) digits is 60480, while the sum is 40.

The square root of 681517066 is about 26105.8818276648. The cubic root of 681517066 is about 880.0193978162.

The spelling of 681517066 in words is "six hundred eighty-one million, five hundred seventeen thousand, sixty-six".