1266123109 has 2 divisors, whose sum is σ = 1266123110. Its totient is φ = 1266123108.

The previous prime is 1266123107. The next prime is 1266123149. The reversal of 1266123109 is 9013216621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 823862209 + 442260900 = 28703^2 + 21030^2 .

It is a cyclic number.

It is not a de Polignac number, because 1266123109 - 2¹ = 1266123107 is a prime.

Together with 1266123107, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1266123101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 633061554 + 633061555.

It is an arithmetic number, because the mean of its divisors is an integer number (633061555).

Almost surely, 2^1266123109 is an apocalyptic number.

It is an amenable number.

1266123109 is a deficient number, since it is larger than the sum of its proper divisors (1).

1266123109 is an equidigital number, since it uses as much as digits as its factorization.

1266123109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 1266123109 is about 35582.6236947193. The cubic root of 1266123109 is about 1081.8290647954.

The spelling of 1266123109 in words is "one billion, two hundred sixty-six million, one hundred twenty-three thousand, one hundred nine".