865088640 has 256 divisors, whose sum is σ = 3300393600. Its totient is φ = 212889600.

The previous prime is 865088603. The next prime is 865088669. The reversal of 865088640 is 46880568.

865088640 is a `hidden beast` number, since 86 + 508 + 8 + 64 + 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 polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 222715 + ... + 226565.

Almost surely, 2^865088640 is an apocalyptic number.

865088640 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 865088640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1650196800).

865088640 is an abundant number, since it is smaller than the sum of its proper divisors (2435304960).

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

865088640 is a wasteful number, since it uses less digits than its factorization.

865088640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3892 (or 3874 counting only the distinct ones).

The product of its (nonzero) digits is 368640, while the sum is 45.

The square root of 865088640 is about 29412.3892263107. The cubic root of 865088640 is about 952.8404883530.

The spelling of 865088640 in words is "eight hundred sixty-five million, eighty-eight thousand, six hundred forty".