1221755 has 4 divisors (see below), whose sum is σ = 1466112. Its totient is φ = 977400.

The previous prime is 1221751. The next prime is 1221761. The reversal of 1221755 is 5571221.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5571221 = 23 ⋅242227.

It is not a de Polignac number, because 1221755 - 2² = 1221751 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221755.

It is not an unprimeable number, because it can be changed into a prime (1221751) 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, 122171 + ... + 122180.

It is an arithmetic number, because the mean of its divisors is an integer number (366528).

2^1221755 is an apocalyptic number.

1221755 is a deficient number, since it is larger than the sum of its proper divisors (244357).

1221755 is an equidigital number, since it uses as much as digits as its factorization.

1221755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244356.

The product of its digits is 700, while the sum is 23.

The square root of 1221755 is about 1105.3302673862. The cubic root of 1221755 is about 106.9041853424.

Adding to 1221755 its reverse (5571221), we get a palindrome (6792976).

The spelling of 1221755 in words is "one million, two hundred twenty-one thousand, seven hundred fifty-five".