1211266221 has 8 divisors (see below), whose sum is σ = 1761841824. Its totient is φ = 734100720.

The previous prime is 1211266219. The next prime is 1211266223. The reversal of 1211266221 is 1226621121.

It is an interprime number because it is at equal distance from previous prime (1211266219) and next prime (1211266223).

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

It is not a de Polignac number, because 1211266221 - 2¹ = 1211266219 is a prime.

It is a super-3 number, since 3×1211266221³ (a number of 28 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1211266191 and 1211266200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211266223) 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, 18352486 + ... + 18352551.

It is an arithmetic number, because the mean of its divisors is an integer number (220230228).

Almost surely, 2^1211266221 is an apocalyptic number.

1211266221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1211266221 is a deficient number, since it is larger than the sum of its proper divisors (550575603).

1211266221 is a wasteful number, since it uses less digits than its factorization.

1211266221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36705051.

The product of its digits is 576, while the sum is 24.

The square root of 1211266221 is about 34803.2501499501. The cubic root of 1211266221 is about 1065.9738118473.

Adding to 1211266221 its reverse (1226621121), we get a palindrome (2437887342).

The spelling of 1211266221 in words is "one billion, two hundred eleven million, two hundred sixty-six thousand, two hundred twenty-one".