1221031011 has 16 divisors (see below), whose sum is σ = 1658764800. Its totient is φ = 798791520.

The previous prime is 1221030997. The next prime is 1221031033. The reversal of 1221031011 is 1101301221.

It is not a de Polignac number, because 1221031011 - 2⁶ = 1221030947 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221031111) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20646 + ... + 53556.

It is an arithmetic number, because the mean of its divisors is an integer number (103672800).

Almost surely, 2^1221031011 is an apocalyptic number.

1221031011 is a deficient number, since it is larger than the sum of its proper divisors (437733789).

1221031011 is a wasteful number, since it uses less digits than its factorization.

1221031011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33146.

The product of its (nonzero) digits is 12, while the sum is 12.

The square root of 1221031011 is about 34943.2541558453. The cubic root of 1221031011 is about 1068.8306470110.

Adding to 1221031011 its reverse (1101301221), we get a palindrome (2322332232).

The spelling of 1221031011 in words is "one billion, two hundred twenty-one million, thirty-one thousand, eleven".