686391066 has 24 divisors (see below), whose sum is σ = 1488910644. Its totient is φ = 228530880.

The previous prime is 686391061. The next prime is 686391071. The reversal of 686391066 is 660193686.

686391066 is a `hidden beast` number, since 6 + 8 + 639 + 1 + 0 + 6 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (686391061) and next prime (686391071).

It can be written as a sum of positive squares in 2 ways, for example, as 628555041 + 57836025 = 25071^2 + 7605^2 .

It is a super-2 number, since 2×686391066² = 942265390969232712, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (686391061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5955 + ... + 37526.

Almost surely, 2^686391066 is an apocalyptic number.

686391066 is an abundant number, since it is smaller than the sum of its proper divisors (802519578).

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

686391066 is a wasteful number, since it uses less digits than its factorization.

686391066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44366 (or 44363 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 45.

The square root of 686391066 is about 26199.0661283947. The cubic root of 686391066 is about 882.1122923035.

The spelling of 686391066 in words is "six hundred eighty-six million, three hundred ninety-one thousand, sixty-six".