865213440 has 352 divisors, whose sum is σ = 3411448320. Its totient is φ = 182255616.

The previous prime is 865213417. The next prime is 865213457. The reversal of 865213440 is 44312568.

It is a congruent number.

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, 1397451 + ... + 1398069.

Almost surely, 2^865213440 is an apocalyptic number.

865213440 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 865213440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1705724160).

865213440 is an abundant number, since it is smaller than the sum of its proper divisors (2546234880).

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

865213440 is a wasteful number, since it uses less digits than its factorization.

865213440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 667 (or 649 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 33.

The square root of 865213440 is about 29414.5107047525. The cubic root of 865213440 is about 952.8863059219.

The spelling of 865213440 in words is "eight hundred sixty-five million, two hundred thirteen thousand, four hundred forty".