686806866 has 12 divisors (see below), whose sum is σ = 1488081582. Its totient is φ = 228935616.

The previous prime is 686806801. The next prime is 686806871. The reversal of 686806866 is 668608686.

It can be written as a sum of positive squares in only one way, i.e., 608855625 + 77951241 = 24675^2 + 8829^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 19077951 + ... + 19077986.

Almost surely, 2^686806866 is an apocalyptic number.

686806866 is an abundant number, since it is smaller than the sum of its proper divisors (801274716).

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

686806866 is a wasteful number, since it uses less digits than its factorization.

686806866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38155945 (or 38155942 counting only the distinct ones).

The product of its (nonzero) digits is 3981312, while the sum is 54.

The square root of 686806866 is about 26207.0003243408. Note that the first 3 decimals coincide. The cubic root of 686806866 is about 882.2903774950.

The spelling of 686806866 in words is "six hundred eighty-six million, eight hundred six thousand, eight hundred sixty-six".