838640 has 40 divisors (see below), whose sum is σ = 2129328. Its totient is φ = 304640.

The previous prime is 838633. The next prime is 838657. The reversal of 838640 is 46838.

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

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 404 + ... + 1356.

2⁸³⁸⁶⁴⁰ is an apocalyptic number.

838640 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 838640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1064664).

838640 is an abundant number, since it is smaller than the sum of its proper divisors (1290688).

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

838640 is a wasteful number, since it uses less digits than its factorization.

838640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 977 (or 971 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 838640 is about 915.7728976116. The cubic root of 838640 is about 94.3029309590.

The spelling of 838640 in words is "eight hundred thirty-eight thousand, six hundred forty".