686798640 has 240 divisors, whose sum is σ = 2664713376. Its totient is φ = 156672000.

The previous prime is 686798621. The next prime is 686798659. The reversal of 686798640 is 46897686.

It is an interprime number because it is at equal distance from previous prime (686798621) and next prime (686798659).

It is a tau number, because it is divible by the number of its divisors (240).

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 132090 + ... + 137190.

Almost surely, 2^686798640 is an apocalyptic number.

686798640 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 686798640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1332356688).

686798640 is an abundant number, since it is smaller than the sum of its proper divisors (1977914736).

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

686798640 is a wasteful number, since it uses less digits than its factorization.

686798640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5148 (or 5139 counting only the distinct ones).

The product of its (nonzero) digits is 3483648, while the sum is 54.

The square root of 686798640 is about 26206.8433810713. The cubic root of 686798640 is about 882.2868550347.

The spelling of 686798640 in words is "six hundred eighty-six million, seven hundred ninety-eight thousand, six hundred forty".