686222640 has 120 divisors (see below), whose sum is σ = 2315999088. Its totient is φ = 182085120.

The previous prime is 686222633. The next prime is 686222651. The reversal of 686222640 is 46222686.

686222640 is a `hidden beast` number, since 6 + 8 + 6 + 2 + 2 + 2 + 640 = 666.

686222640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 686222595 and 686222604.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 149662 + ... + 154178.

Almost surely, 2^686222640 is an apocalyptic number.

686222640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 686222640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1157999544).

686222640 is an abundant number, since it is smaller than the sum of its proper divisors (1629776448).

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

686222640 is a wasteful number, since it uses less digits than its factorization.

686222640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4747 (or 4738 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

The square root of 686222640 is about 26195.8515799735. The cubic root of 686222640 is about 882.0401357706.

The spelling of 686222640 in words is "six hundred eighty-six million, two hundred twenty-two thousand, six hundred forty".