1266523221 has 16 divisors (see below), whose sum is σ = 1773803520. Its totient is φ = 802282800.

The previous prime is 1266523213. The next prime is 1266523229. The reversal of 1266523221 is 1223256621.

It is an interprime number because it is at equal distance from previous prime (1266523213) and next prime (1266523229).

It is not a de Polignac number, because 1266523221 - 2³ = 1266523213 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1266523229) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50361 + ... + 71198.

It is an arithmetic number, because the mean of its divisors is an integer number (110862720).

Almost surely, 2^1266523221 is an apocalyptic number.

It is an amenable number.

1266523221 is a deficient number, since it is larger than the sum of its proper divisors (507280299).

1266523221 is a wasteful number, since it uses less digits than its factorization.

1266523221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121736.

The product of its digits is 8640, while the sum is 30.

The square root of 1266523221 is about 35588.2455454045. The cubic root of 1266523221 is about 1081.9430103246.

Adding to 1266523221 its reverse (1223256621), we get a palindrome (2489779842).

The spelling of 1266523221 in words is "one billion, two hundred sixty-six million, five hundred twenty-three thousand, two hundred twenty-one".