684206640 has 180 divisors, whose sum is σ = 2488586256. Its totient is φ = 168390144.

The previous prime is 684206609. The next prime is 684206671. The reversal of 684206640 is 46602486.

It is a happy number.

684206640 is a `hidden beast` number, since 6 + 8 + 4 + 2 + 0 + 6 + 640 = 666.

It is an interprime number because it is at equal distance from previous prime (684206609) and next prime (684206671).

It is a tau number, because it is divible by the number of its divisors (180).

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 = 684206595 and 684206604.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 118869 + ... + 124491.

Almost surely, 2^684206640 is an apocalyptic number.

684206640 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 684206640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1244293128).

684206640 is an abundant number, since it is smaller than the sum of its proper divisors (1804379616).

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

684206640 is a wasteful number, since it uses less digits than its factorization.

684206640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5668 (or 5646 counting only the distinct ones).

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

The square root of 684206640 is about 26157.3439018567. The cubic root of 684206640 is about 881.1755295453.

The spelling of 684206640 in words is "six hundred eighty-four million, two hundred six thousand, six hundred forty".