7856684640 has 1152 divisors, whose sum is σ = 35649331200. Its totient is φ = 1579253760.

The previous prime is 7856684593. The next prime is 7856684663. The reversal of 7856684640 is 464866587.

7856684640 is a `hidden beast` number, since 78 + 56 + 68 + 464 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

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 191 ways as a sum of consecutive naturals, for example, 253441425 + ... + 253441455.

It is an arithmetic number, because the mean of its divisors is an integer number (30945600).

Almost surely, 2^7856684640 is an apocalyptic number.

7856684640 is a gapful number since it is divisible by the number (70) 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 7856684640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (17824665600).

7856684640 is an abundant number, since it is smaller than the sum of its proper divisors (27792646560).

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

7856684640 is a wasteful number, since it uses less digits than its factorization.

7856684640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125 (or 94 counting only the distinct ones).

The product of its (nonzero) digits is 7741440, while the sum is 54.

The square root of 7856684640 is about 88637.9413118333. The cubic root of 7856684640 is about 1987.9850179769.

The spelling of 7856684640 in words is "seven billion, eight hundred fifty-six million, six hundred eighty-four thousand, six hundred forty".