1021122221 has 48 divisors (see below), whose sum is σ = 1299777840. Its totient is φ = 796723200.

The previous prime is 1021122209. The next prime is 1021122251. The reversal of 1021122221 is 1222211201.

It can be written as a sum of positive squares in 8 ways, for example, as 541074121 + 480048100 = 23261^2 + 21910^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1021122221 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1021122196 and 1021122205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021122251) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4458935 + ... + 4459163.

It is an arithmetic number, because the mean of its divisors is an integer number (27078705).

Almost surely, 2^1021122221 is an apocalyptic number.

It is an amenable number.

1021122221 is a deficient number, since it is larger than the sum of its proper divisors (278655619).

1021122221 is a wasteful number, since it uses less digits than its factorization.

1021122221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414 (or 407 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 1021122221 is about 31955.0030668126. The cubic root of 1021122221 is about 1006.9917419487.

Adding to 1021122221 its reverse (1222211201), we get a palindrome (2243333422).

The spelling of 1021122221 in words is "one billion, twenty-one million, one hundred twenty-two thousand, two hundred twenty-one".