1266997257 has 6 divisors (see below), whose sum is σ = 1830107162. Its totient is φ = 844664832.

The previous prime is 1266997243. The next prime is 1266997309. The reversal of 1266997257 is 7527996621.

It can be written as a sum of positive squares in only one way, i.e., 1106493696 + 160503561 = 33264^2 + 12669^2 .

It is not a de Polignac number, because 1266997257 - 2¹¹ = 1266995209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1266997057) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 70388728 + ... + 70388745.

Almost surely, 2^1266997257 is an apocalyptic number.

It is an amenable number.

1266997257 is a deficient number, since it is larger than the sum of its proper divisors (563109905).

1266997257 is a wasteful number, since it uses less digits than its factorization.

1266997257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140777479 (or 140777476 counting only the distinct ones).

The product of its digits is 2857680, while the sum is 54.

The square root of 1266997257 is about 35594.9049303408. The cubic root of 1266997257 is about 1082.0779771783.

It can be divided in two parts, 126699 and 7257, that added together give a square (133956 = 366²).

The spelling of 1266997257 in words is "one billion, two hundred sixty-six million, nine hundred ninety-seven thousand, two hundred fifty-seven".