1221320235 has 16 divisors (see below), whose sum is σ = 2006927136. Its totient is φ = 633765888.

The previous prime is 1221320227. The next prime is 1221320251. The reversal of 1221320235 is 5320231221.

It is not a de Polignac number, because 1221320235 - 2³ = 1221320227 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1099734 + ... + 1100843.

It is an arithmetic number, because the mean of its divisors is an integer number (125432946).

Almost surely, 2^1221320235 is an apocalyptic number.

1221320235 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1221320235 is a deficient number, since it is larger than the sum of its proper divisors (785606901).

1221320235 is a wasteful number, since it uses less digits than its factorization.

1221320235 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2200622.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 1221320235 is about 34947.3923919940. The cubic root of 1221320235 is about 1068.9150311824.

Adding to 1221320235 its reverse (5320231221), we get a palindrome (6541551456).

The spelling of 1221320235 in words is "one billion, two hundred twenty-one million, three hundred twenty thousand, two hundred thirty-five".