1221152011 has 4 divisors (see below), whose sum is σ = 1224841624. Its totient is φ = 1217462400.

The previous prime is 1221152003. The next prime is 1221152027. The reversal of 1221152011 is 1102511221.

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 1221152011 - 2³ = 1221152003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221152081) 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, 1844310 + ... + 1844971.

It is an arithmetic number, because the mean of its divisors is an integer number (306210406).

Almost surely, 2^1221152011 is an apocalyptic number.

1221152011 is a deficient number, since it is larger than the sum of its proper divisors (3689613).

1221152011 is an equidigital number, since it uses as much as digits as its factorization.

1221152011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3689612.

The product of its (nonzero) digits is 40, while the sum is 16.

The square root of 1221152011 is about 34944.9854914836. The cubic root of 1221152011 is about 1068.8659516662.

Adding to 1221152011 its reverse (1102511221), we get a palindrome (2323663232).

The spelling of 1221152011 in words is "one billion, two hundred twenty-one million, one hundred fifty-two thousand, eleven".