631218 has 48 divisors (see below), whose sum is σ = 1559520. Its totient is φ = 169344.

The previous prime is 631187. The next prime is 631223. The reversal of 631218 is 812136.

It is a Harshad number since it is a multiple of its sum of digits (21).

Its product of digits (288) is a multiple of the sum of its prime divisors (144).

It is a junction number, because it is equal to n+sod(n) for n = 631194 and 631203.

It is an unprimeable number.

631218 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 23 ways as a sum of consecutive naturals, for example, 5530 + ... + 5642.

It is an arithmetic number, because the mean of its divisors is an integer number (32490).

2⁶³¹²¹⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 631218, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (779760).

631218 is an abundant number, since it is smaller than the sum of its proper divisors (928302).

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

631218 is a wasteful number, since it uses less digits than its factorization.

631218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151 (or 144 counting only the distinct ones).

The product of its digits is 288, while the sum is 21.

The square root of 631218 is about 794.4922907115. The cubic root of 631218 is about 85.7813990246.

The spelling of 631218 in words is "six hundred thirty-one thousand, two hundred eighteen".