1221045 has 32 divisors (see below), whose sum is σ = 2315520. Its totient is φ = 537600.

The previous prime is 1221029. The next prime is 1221049. The reversal of 1221045 is 5401221.

It is not a de Polignac number, because 1221045 - 2⁴ = 1221029 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

1221045 is a lucky number.

It is a nialpdrome in base 11.

It is a congruent number.

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 31 ways as a sum of consecutive naturals, for example, 2845 + ... + 3245.

It is an arithmetic number, because the mean of its divisors is an integer number (72360).

2^1221045 is an apocalyptic number.

1221045 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221045 is a deficient number, since it is larger than the sum of its proper divisors (1094475).

1221045 is a wasteful number, since it uses less digits than its factorization.

1221045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 445.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 1221045 is about 1105.0090497367. The cubic root of 1221045 is about 106.8834728757.

Adding to 1221045 its reverse (5401221), we get a palindrome (6622266).

The spelling of 1221045 in words is "one million, two hundred twenty-one thousand, forty-five".