1221587 has 4 divisors (see below), whose sum is σ = 1250040. Its totient is φ = 1193136.

The previous prime is 1221559. The next prime is 1221589. The reversal of 1221587 is 7851221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1221587 - 2⁶ = 1221523 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14162 + ... + 14247.

It is an arithmetic number, because the mean of its divisors is an integer number (312510).

2^1221587 is an apocalyptic number.

1221587 is a deficient number, since it is larger than the sum of its proper divisors (28453).

1221587 is an equidigital number, since it uses as much as digits as its factorization.

1221587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28452.

The product of its digits is 1120, while the sum is 26.

The square root of 1221587 is about 1105.2542693878. The cubic root of 1221587 is about 106.8992850892.

The spelling of 1221587 in words is "one million, two hundred twenty-one thousand, five hundred eighty-seven".