1220840 has 32 divisors (see below), whose sum is σ = 2868480. Its totient is φ = 466752.

The previous prime is 1220839. The next prime is 1220893. The reversal of 1220840 is 480221.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 257 + ... + 1583.

It is an arithmetic number, because the mean of its divisors is an integer number (89640).

2^1220840 is an apocalyptic number.

1220840 is a gapful number since it is divisible by the number (10) 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 1220840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1434240).

1220840 is an abundant number, since it is smaller than the sum of its proper divisors (1647640).

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

1220840 is a wasteful number, since it uses less digits than its factorization.

1220840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1361 (or 1357 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 1220840 is about 1104.9162864217. The cubic root of 1220840 is about 106.8774910218.

The spelling of 1220840 in words is "one million, two hundred twenty thousand, eight hundred forty".