1266939957 has 4 divisors (see below), whose sum is σ = 1689253280. Its totient is φ = 844626636.

The previous prime is 1266939913. The next prime is 1266939979. The reversal of 1266939957 is 7599396621.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 7599396621 = 3 ⋅2533132207.

It is not a de Polignac number, because 1266939957 - 2¹⁶ = 1266874421 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1266939897 and 1266939906.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1266939257) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 211156657 + ... + 211156662.

It is an arithmetic number, because the mean of its divisors is an integer number (422313320).

Almost surely, 2^1266939957 is an apocalyptic number.

It is an amenable number.

1266939957 is a deficient number, since it is larger than the sum of its proper divisors (422313323).

1266939957 is an equidigital number, since it uses as much as digits as its factorization.

1266939957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422313322.

The product of its digits is 5511240, while the sum is 57.

The square root of 1266939957 is about 35594.1000307635. The cubic root of 1266939957 is about 1082.0616645930.

The spelling of 1266939957 in words is "one billion, two hundred sixty-six million, nine hundred thirty-nine thousand, nine hundred fifty-seven".