1211122021 has 4 divisors (see below), whose sum is σ = 1218836332. Its totient is φ = 1203407712.

The previous prime is 1211122019. The next prime is 1211122037. The reversal of 1211122021 is 1202211121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1202211121 = 71 ⋅16932551.

It can be written as a sum of positive squares in 2 ways, for example, as 565250625 + 645871396 = 23775^2 + 25414^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211122021 - 2¹ = 1211122019 is a prime.

It is a super-2 number, since 2×1211122021² = 2933633099502248882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211121992 and 1211122010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211122321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3856920 + ... + 3857233.

It is an arithmetic number, because the mean of its divisors is an integer number (304709083).

Almost surely, 2^1211122021 is an apocalyptic number.

It is an amenable number.

1211122021 is a deficient number, since it is larger than the sum of its proper divisors (7714311).

1211122021 is an equidigital number, since it uses as much as digits as its factorization.

1211122021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7714310.

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 1211122021 is about 34801.1784426907. The cubic root of 1211122021 is about 1065.9315091393.

Adding to 1211122021 its reverse (1202211121), we get a palindrome (2413333142).

The spelling of 1211122021 in words is "one billion, two hundred eleven million, one hundred twenty-two thousand, twenty-one".