634840 has 32 divisors (see below), whose sum is σ = 1458000. Its totient is φ = 248704.

The previous prime is 634817. The next prime is 634841. The reversal of 634840 is 48436.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (634841) by changing a digit.

634840 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, 2226 + ... + 2494.

2⁶³⁴⁸⁴⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 634840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (729000).

634840 is an abundant number, since it is smaller than the sum of its proper divisors (823160).

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

634840 is a wasteful number, since it uses less digits than its factorization.

634840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339 (or 335 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 634840 is about 796.7684732719. The cubic root of 634840 is about 85.9451606394.

The spelling of 634840 in words is "six hundred thirty-four thousand, eight hundred forty".