1221287 has 4 divisors (see below), whose sum is σ = 1223880. Its totient is φ = 1218696.

The previous prime is 1221251. The next prime is 1221289. The reversal of 1221287 is 7821221.

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 1221287 - 2⁶ = 1221223 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221289) 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, 368 + ... + 1605.

It is an arithmetic number, because the mean of its divisors is an integer number (305970).

2^1221287 is an apocalyptic number.

1221287 is a deficient number, since it is larger than the sum of its proper divisors (2593).

1221287 is an equidigital number, since it uses as much as digits as its factorization.

1221287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2592.

The product of its digits is 448, while the sum is 23.

The square root of 1221287 is about 1105.1185456773. The cubic root of 1221287 is about 106.8905335196.

The spelling of 1221287 in words is "one million, two hundred twenty-one thousand, two hundred eighty-seven".