1211010221 has 4 divisors (see below), whose sum is σ = 1214500512. Its totient is φ = 1207519932.

The previous prime is 1211010211. The next prime is 1211010323. The reversal of 1211010221 is 1220101121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1220101121 = 491 ⋅2484931.

It is a cyclic number.

It is not a de Polignac number, because 1211010221 - 2¹⁴ = 1210993837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211010211) 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, 1744625 + ... + 1745318.

It is an arithmetic number, because the mean of its divisors is an integer number (303625128).

Almost surely, 2^1211010221 is an apocalyptic number.

It is an amenable number.

1211010221 is a deficient number, since it is larger than the sum of its proper divisors (3490291).

1211010221 is an equidigital number, since it uses as much as digits as its factorization.

1211010221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3490290.

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 1211010221 is about 34799.5721381743. The cubic root of 1211010221 is about 1065.8987090284.

Adding to 1211010221 its reverse (1220101121), we get a palindrome (2431111342).

The spelling of 1211010221 in words is "one billion, two hundred eleven million, ten thousand, two hundred twenty-one".