1211122221 has 8 divisors (see below), whose sum is σ = 1658473824. Its totient is φ = 785592720.

The previous prime is 1211122207. The next prime is 1211122261. The reversal of 1211122221 is 1222211121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1211122221 - 2¹³ = 1211114029 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1211122221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211122261) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5455395 + ... + 5455616.

It is an arithmetic number, because the mean of its divisors is an integer number (207309228).

Almost surely, 2^1211122221 is an apocalyptic number.

It is an amenable number.

1211122221 is a deficient number, since it is larger than the sum of its proper divisors (447351603).

1211122221 is a wasteful number, since it uses less digits than its factorization.

1211122221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10911051.

The product of its digits is 32, while the sum is 15.

The square root of 1211122221 is about 34801.1813161565. The cubic root of 1211122221 is about 1065.9315678139.

Adding to 1211122221 its reverse (1222211121), we get a palindrome (2433333342).

Subtracting 1211122221 from its reverse (1222211121), we obtain a square (11088900 = 3330²).

The spelling of 1211122221 in words is "one billion, two hundred eleven million, one hundred twenty-two thousand, two hundred twenty-one".