1011212221 has 4 divisors (see below), whose sum is σ = 1017267552. Its totient is φ = 1005156892.

The previous prime is 1011212177. The next prime is 1011212231. The reversal of 1011212221 is 1222121101.

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: 1222121101 = 761 ⋅1605941.

It is a cyclic number.

It is not a de Polignac number, because 1011212221 - 2⁷ = 1011212093 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 (1011212231) 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, 3027415 + ... + 3027748.

It is an arithmetic number, because the mean of its divisors is an integer number (254316888).

Almost surely, 2^1011212221 is an apocalyptic number.

It is an amenable number.

1011212221 is a deficient number, since it is larger than the sum of its proper divisors (6055331).

1011212221 is an equidigital number, since it uses as much as digits as its factorization.

1011212221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6055330.

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

The square root of 1011212221 is about 31799.5632202708. The cubic root of 1011212221 is about 1003.7235251520.

Adding to 1011212221 its reverse (1222121101), we get a palindrome (2233333322).

The spelling of 1011212221 in words is "one billion, eleven million, two hundred twelve thousand, two hundred twenty-one".