6291386640 has 640 divisors, whose sum is σ = 27409674240. Its totient is φ = 1304501760.

The previous prime is 6291386623. The next prime is 6291386659. The reversal of 6291386640 is 466831926.

6291386640 is a `hidden beast` number, since 629 + 13 + 8 + 6 + 6 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 13471687 + ... + 13472153.

It is an arithmetic number, because the mean of its divisors is an integer number (42827616).

Almost surely, 2^6291386640 is an apocalyptic number.

6291386640 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 6291386640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13704837120).

6291386640 is an abundant number, since it is smaller than the sum of its proper divisors (21118287600).

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

6291386640 is a wasteful number, since it uses less digits than its factorization.

6291386640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 519 (or 495 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The square root of 6291386640 is about 79318.2617056123. The cubic root of 6291386640 is about 1846.0726659496.

The spelling of 6291386640 in words is "six billion, two hundred ninety-one million, three hundred eighty-six thousand, six hundred forty".