247840 has 24 divisors (see below), whose sum is σ = 585900. Its totient is φ = 99072.

The previous prime is 247829. The next prime is 247847. The reversal of 247840 is 48742.

It can be written as a sum of positive squares in 2 ways, for example, as 242064 + 5776 = 492^2 + 76^2 .

It is a super-2 number, since 2×247840² = 122849331200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (247847) by changing a digit.

247840 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 3 ways as a sum of consecutive naturals, for example, 615 + ... + 934.

2²⁴⁷⁸⁴⁰ is an apocalyptic number.

247840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

247840 is an abundant number, since it is smaller than the sum of its proper divisors (338060).

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

247840 is a wasteful number, since it uses less digits than its factorization.

247840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1564 (or 1556 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 25.

The square root of 247840 is about 497.8353141351. The cubic root of 247840 is about 62.8140988265.

The spelling of 247840 in words is "two hundred forty-seven thousand, eight hundred forty".