249640 has 24 divisors (see below), whose sum is σ = 568890. Its totient is φ = 98592.

The previous prime is 249607. The next prime is 249647. The reversal of 249640 is 46942.

249640 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 224676 + 24964 = 474^2 + 158^2 .

It is not an unprimeable number, because it can be changed into a prime (249647) by changing a digit.

249640 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 5 ways as a sum of consecutive naturals, for example, 3121 + ... + 3199.

2²⁴⁹⁶⁴⁰ is an apocalyptic number.

249640 is a gapful number since it is divisible by the number (20) 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 249640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (284445).

249640 is an abundant number, since it is smaller than the sum of its proper divisors (319250).

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

249640 is an equidigital number, since it uses as much as digits as its factorization.

249640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169 (or 86 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 249640 is about 499.6398703066. The cubic root of 249640 is about 62.9657998636.

The spelling of 249640 in words is "two hundred forty-nine thousand, six hundred forty".