1226158721 has 2 divisors, whose sum is σ = 1226158722. Its totient is φ = 1226158720.

The previous prime is 1226158699. The next prime is 1226158723. The reversal of 1226158721 is 1278516221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1215498496 + 10660225 = 34864^2 + 3265^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1226158721 is a prime.

It is a Sophie Germain prime.

Together with 1226158723, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1226158723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 613079360 + 613079361.

It is an arithmetic number, because the mean of its divisors is an integer number (613079361).

Almost surely, 2^1226158721 is an apocalyptic number.

It is an amenable number.

1226158721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1226158721 is an equidigital number, since it uses as much as digits as its factorization.

1226158721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13440, while the sum is 35.

The square root of 1226158721 is about 35016.5492446072. The cubic root of 1226158721 is about 1070.3247394104.

The spelling of 1226158721 in words is "one billion, two hundred twenty-six million, one hundred fifty-eight thousand, seven hundred twenty-one".