1211555 has 8 divisors (see below), whose sum is σ = 1460592. Its totient is φ = 964768.

The previous prime is 1211549. The next prime is 1211563. The reversal of 1211555 is 5551121.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1211555 - 2¹⁴ = 1195171 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1052 + ... + 1878.

It is an arithmetic number, because the mean of its divisors is an integer number (182574).

2^1211555 is an apocalyptic number.

1211555 is a deficient number, since it is larger than the sum of its proper divisors (249037).

1211555 is an equidigital number, since it uses as much as digits as its factorization.

1211555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1125.

The product of its digits is 250, while the sum is 20.

The square root of 1211555 is about 1100.7065912404. The cubic root of 1211555 is about 106.6058518354.

Adding to 1211555 its reverse (5551121), we get a palindrome (6762676).

The spelling of 1211555 in words is "one million, two hundred eleven thousand, five hundred fifty-five".