864386640 has 400 divisors, whose sum is σ = 3347452416. Its totient is φ = 205286400.

The previous prime is 864386623. The next prime is 864386647. The reversal of 864386640 is 46683468.

864386640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (864386647) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 2611275 + ... + 2611605.

Almost surely, 2^864386640 is an apocalyptic number.

864386640 is a gapful number since it is divisible by the number (80) 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 864386640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1673726208).

864386640 is an abundant number, since it is smaller than the sum of its proper divisors (2483065776).

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

864386640 is a wasteful number, since it uses less digits than its factorization.

864386640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 400 (or 385 counting only the distinct ones).

The product of its (nonzero) digits is 663552, while the sum is 45.

The square root of 864386640 is about 29400.4530577337. The cubic root of 864386640 is about 952.5826823879.

The spelling of 864386640 in words is "eight hundred sixty-four million, three hundred eighty-six thousand, six hundred forty".