1221860 has 24 divisors (see below), whose sum is σ = 2587200. Its totient is φ = 484704.

The previous prime is 1221853. The next prime is 1221863. The reversal of 1221860 is 681221.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (1221863) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3827 + ... + 4133.

It is an arithmetic number, because the mean of its divisors is an integer number (107800).

2^1221860 is an apocalyptic number.

1221860 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221860 is an abundant number, since it is smaller than the sum of its proper divisors (1365340).

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

1221860 is a wasteful number, since it uses less digits than its factorization.

1221860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 515 (or 513 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 1221860 is about 1105.3777634818. The cubic root of 1221860 is about 106.9072477725.

The spelling of 1221860 in words is "one million, two hundred twenty-one thousand, eight hundred sixty".