655840 has 24 divisors (see below), whose sum is σ = 1549800. Its totient is φ = 262272.

The previous prime is 655807. The next prime is 655847. The reversal of 655840 is 48556.

It is a super-2 number, since 2×655840² = 860252211200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 655799 and 655808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (655847) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1890 + ... + 2209.

It is an arithmetic number, because the mean of its divisors is an integer number (64575).

2⁶⁵⁵⁸⁴⁰ is an apocalyptic number.

It is an amenable number.

655840 is an abundant number, since it is smaller than the sum of its proper divisors (893960).

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

655840 is a wasteful number, since it uses less digits than its factorization.

655840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4114 (or 4106 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 28.

The square root of 655840 is about 809.8394902695. The cubic root of 655840 is about 86.8825649434.

The spelling of 655840 in words is "six hundred fifty-five thousand, eight hundred forty".