1221040 has 20 divisors (see below), whose sum is σ = 2839104. Its totient is φ = 488384.

The previous prime is 1221029. The next prime is 1221049. The reversal of 1221040 is 401221.

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (1221049) 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, 7552 + ... + 7711.

2^1221040 is an apocalyptic number.

1221040 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221040 is an abundant number, since it is smaller than the sum of its proper divisors (1618064).

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

1221040 is a wasteful number, since it uses less digits than its factorization.

1221040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15276 (or 15270 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 1221040 is about 1105.0067873095. The cubic root of 1221040 is about 106.8833269848.

Adding to 1221040 its reverse (401221), we get a palindrome (1622261).

The spelling of 1221040 in words is "one million, two hundred twenty-one thousand, forty".