2221122821 has 2 divisors, whose sum is σ = 2221122822. Its totient is φ = 2221122820.

The previous prime is 2221122793. The next prime is 2221122823. The reversal of 2221122821 is 1282211222.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1232712100 + 988410721 = 35110^2 + 31439^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2221122821 is a prime.

Together with 2221122823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2221122823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1110561410 + 1110561411.

It is an arithmetic number, because the mean of its divisors is an integer number (1110561411).

Almost surely, 2^2221122821 is an apocalyptic number.

It is an amenable number.

2221122821 is a deficient number, since it is larger than the sum of its proper divisors (1).

2221122821 is an equidigital number, since it uses as much as digits as its factorization.

2221122821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 512, while the sum is 23.

The square root of 2221122821 is about 47128.7897256019. The cubic root of 2221122821 is about 1304.7406443776.

The spelling of 2221122821 in words is "two billion, two hundred twenty-one million, one hundred twenty-two thousand, eight hundred twenty-one".