869840 has 40 divisors (see below), whose sum is σ = 2062368. Its totient is φ = 341120.

The previous prime is 869819. The next prime is 869849. The reversal of 869840 is 48968.

It is a tau number, because it is divible by the number of its divisors (40).

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 869840.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 869840.

It is not an unprimeable number, because it can be changed into a prime (869849) by changing a digit.

869840 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6575 + ... + 6705.

2⁸⁶⁹⁸⁴⁰ is an apocalyptic number.

869840 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 869840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1031184).

869840 is an abundant number, since it is smaller than the sum of its proper divisors (1192528).

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

869840 is a wasteful number, since it uses less digits than its factorization.

869840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227 (or 221 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 869840 is about 932.6521323623. The cubic root of 869840 is about 95.4581745339.

The spelling of 869840 in words is "eight hundred sixty-nine thousand, eight hundred forty".