686542864 has 80 divisors (see below), whose sum is σ = 1589739520. Its totient is φ = 281024640.

The previous prime is 686542849. The next prime is 686542891. The reversal of 686542864 is 468245686.

It is a super-2 number, since 2×686542864² = 942682208218644992, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 273037 + ... + 275539.

It is an arithmetic number, because the mean of its divisors is an integer number (19871744).

Almost surely, 2^686542864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 686542864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (794869760).

686542864 is an abundant number, since it is smaller than the sum of its proper divisors (903196656).

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

686542864 is a wasteful number, since it uses less digits than its factorization.

686542864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2628 (or 2622 counting only the distinct ones).

The product of its digits is 2211840, while the sum is 49.

The square root of 686542864 is about 26201.9629798990. The cubic root of 686542864 is about 882.1773150087.

It can be divided in two parts, 6865 and 42864, that added together give a square (49729 = 223²).

The spelling of 686542864 in words is "six hundred eighty-six million, five hundred forty-two thousand, eight hundred sixty-four".