631840 has 48 divisors (see below), whose sum is σ = 1632960. Its totient is φ = 229120.

The previous prime is 631819. The next prime is 631843. The reversal of 631840 is 48136.

631840 = 79² + 80² + ... + 133².

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (631843) by changing a digit.

631840 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, 1581 + ... + 1939.

It is an arithmetic number, because the mean of its divisors is an integer number (34020).

2⁶³¹⁸⁴⁰ 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 631840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (816480).

631840 is an abundant number, since it is smaller than the sum of its proper divisors (1001120).

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

631840 is a wasteful number, since it uses less digits than its factorization.

631840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385 (or 377 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 631840 is about 794.8836392831. The cubic root of 631840 is about 85.8095660045.

Adding to 631840 its reverse (48136), we get a palindrome (679976).

The spelling of 631840 in words is "six hundred thirty-one thousand, eight hundred forty".