1221011211 has 32 divisors (see below), whose sum is σ = 1937875968. Its totient is φ = 669271680.

The previous prime is 1221011177. The next prime is 1221011221. The reversal of 1221011211 is 1121101221.

It is not a de Polignac number, because 1221011211 - 2¹⁵ = 1220978443 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221011221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 44101 + ... + 66233.

It is an arithmetic number, because the mean of its divisors is an integer number (60558624).

Almost surely, 2^1221011211 is an apocalyptic number.

1221011211 is a deficient number, since it is larger than the sum of its proper divisors (716864757).

1221011211 is a wasteful number, since it uses less digits than its factorization.

1221011211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22251.

The product of its (nonzero) digits is 8, while the sum is 12.

The square root of 1221011211 is about 34942.9708382101. The cubic root of 1221011211 is about 1068.8248696635.

Adding to 1221011211 its reverse (1121101221), we get a palindrome (2342112432).

The spelling of 1221011211 in words is "one billion, two hundred twenty-one million, eleven thousand, two hundred eleven".