1221887 has 4 divisors (see below), whose sum is σ = 1224360. Its totient is φ = 1219416.

The previous prime is 1221863. The next prime is 1221907. The reversal of 1221887 is 7881221.

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 1221887 - 2⁶ = 1221823 is a prime.

It is a super-3 number, since 3×1221887³ = 5472860614601133309, which contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1224887) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 212 + ... + 1577.

It is an arithmetic number, because the mean of its divisors is an integer number (306090).

2^1221887 is an apocalyptic number.

1221887 is a deficient number, since it is larger than the sum of its proper divisors (2473).

1221887 is an equidigital number, since it uses as much as digits as its factorization.

1221887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2472.

The product of its digits is 1792, while the sum is 29.

The square root of 1221887 is about 1105.3899764337. The cubic root of 1221887 is about 106.9080352262.

The spelling of 1221887 in words is "one million, two hundred twenty-one thousand, eight hundred eighty-seven".